Method and apparatus for increasing receiver immunity to interference.
Abstract
The method and apparatus of the present invention improve the immunity to interference of a radio receiver. The power level of a received signal is detected. If the power level meets or exceeds a predetermined power threshold, the low noise amplifier (703) is by-passed (730), thus increasing the intercept point of the receiver components. Alternative embodiments include the use of an RF power detector (105) to control the front-end gain (110) as a function of jammer power. In lieu of a switchable RF gain block (730), several methods of continuous gain control are proposed. Continuous gain control allows the interference suppression and sensitivity of the receiver to be adjusted at lower signal levels than the switchable gain block. A method of the present invention adjusts the input gain by a predetermined amount (1601). The receiver processing measures the gain change in the IF signal power (1605). If the change is less than the predetermined amount (1610), the CDMA signal and jammers are below the noise floor and, therefore, the gain is increased (1615). If the IF signal power change is greater than the predetermined amount, the interference is evident and the gain is reduced to reduce the intermodulation products (1620). This process is used until the receiver is operating at the best compromise between interference and noise figure.

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31 claims: 12 independent, 19 dependent
- 1NOVEDAD DE LA INVENCIÓN Habiendo descrito la presente invención se considera como novedad y por lo tanto se reclama como propiedad lo descrito en las siguientes reivindicaciones. 1. Un aparato para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal, el aparato comprende:un primer conmutador acoplado a la señal recibida, teniendo el primer conmutador una primer posición y una segunda posición, acoplándose la segunda posición a una trayectoria de derivación;un amplificador, acoplado a la primera posición del primer conmutador, para amplificar la señal recibida;un segundo conmutador que tiene una primera posición y una segunda posición, la primer posición acoplada al amplificador y acoplándose la segunda posición a la trayectoria de derivación;y un controlador acoplado al primer conmutador y al segundo conmutador, conmutando el controlador los conmutadores, primero y segundo, a las segundas posiciones en respuesta a la señal recibida que excede un nivel de potencia predeterminado.
- 2El aparato según la reivindicación 1, caracterizado porque el nivel de potencia predeterminado es de -65 dBm.
- 3El aparato según la reivindicación 1, caracterizado porque el amplificador es un amplificador de -2828 ruido bajo.
- 4Un aparato para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal, el aparato comprende:un conmutador acoplado a la señal recibida, teniendo el conmutador una posición abierta y una posición cerrada, acoplándose la posición cerrada a una trayectoria de derivación;un primer amplificador que tiene una entrada acoplada a la primera posición del conmutador y una salida acoplada a la trayectoria de derivación;y un controlador acoplado al primer conmutador para conmutar el conmutador a la posición cerrada en respuesta a la señal recibida que excede un nivel de potencia predeterminado.
- 5El aparato según la reivindicación 4, caracterizado porque comprende además:un filtro acoplado a la salida del primer amplificador, emitiendo el filtro una señal recibida filtrada en una salida del filtro;un oscilador para generar una señal osciladora que tiene una frecuencia predeterminada;una mezcladora, que tiene una primera entrada y una segunda entrada, encontrándose la primera entrada acoplada a la salida de filtro y acoplándose la segunda entrada al oscilador, generando la mezcladora una señal subconvertida en respuesta a la señal osciladora y la señal recibida filtrada;un segundo amplificador acoplado a la señal subconvertida;un tercer -2929 amplificador acoplado a la señal subconvertida;un primer filtro de onda de acústica superficial, acoplado al segundo amplificador, para generar una señal para utilizarse en un sistema radiotelefónico digital;y un segundo filtro de onda acústica superficial, acoplado al tercer amplificador, para generar una señal para utilizarse en un sistema radiotelefónico análogo.
- 6Un aparato para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal, el aparato comprende:un conmutador acoplado a la señal recibida, teniendo el conmutador una posición abierta y una posición cerrada;una resistencia, acoplándose un primer extremo de la resistencia a la posición cerrada del conmutador y acoplándose un segundo extremo de la resistencia a un potencial de tierra;un amplificador que tiene una entrada acoplada a la posición abierta del conmutador para generar una señal recibida amplificada en una salida;y un controlador acoplado al conmutador para conmutar el conmutador a la posición cerrada en respuesta a la señal recibida que excede un nivel de potencia predeterminado.
- 7Un aparato para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal, el aparato comprende:un amplificador, que tiene una entrada acopiada -3030 a la señal recibida, para generar una señal recibida amplificada en una salida;una trayectoria de derivación acoplada a la entrada del amplificador;un conmutador que tiene una primer posición y una segunda posición, acoplándose la primer posición a la salida del amplificador y acoplándose la segunda posición a la trayectoria de derivación;y un controlador acoplado al conmutador para conmutar el conmutador desde la primer posición a la segundo posición en respuesta a la señal recibida que excede un nivel de potencia predeterminado.
- 8Un método para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, teniendo el radioreceptor un amplificador de recepción y recibiendo una señal de radio, el método comprende las etapas de:detectar un nivel de potencia de la señal de radio recibida;y si el nivel de potencia es igual o mayor a un umbral predeterminado, disminuir la ganancia del amplificador de recepción.
- 9El método según la reivindicación 8, caracterizado porque la etapa de disminuir la ganancia del amplificador de recepción incluye la derivación del amplificador de recepción.
- 10El método según la reivindicación 8, caracterizado porque la etapa de disminuir la ganancia del amplificador de recepción incluye la generación de un error -3131 de comparación de impedancia entre la señal de radio recibida y el amplificador de recepción.
- 11Un aparato para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal, el aparato comprende:un amplificador acoplado a la señal recibida para amplificar la señal recibida;un control automático de ganancia de recepción que tiene una entrada acoplada a la señal amplificada y una salida;un detector de potencia acoplado a la salida del control automático de ganancia de recepción, ajustando el detector de potencia el control automático de ganancia de recepción en respuesta a una potencia detectada de la señal recibida.
- 12Un aparato para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal en una antena, el aparato comprende:un duplexor para separar una trayectoria de transmisión desde una trayectoria de recepción, el duplexor acoplado a la antena;un amplificador de recepción, en la trayectoria de recepción, acoplado al duplexor para amplificar la señal recibida;un control automático de ganancia de recepción, en la trayectoria de recepción, que tiene una salida y una entrada acopladas a la señal amplificada;un control automático de ganancia de transmisión, en la trayectoria de transmisión, que tiene -3232 una salida y una entrada acopladas a una señal por transmitirse;un amplificador de potencia de transmisión, en la trayectoria de transmisión, que tiene una entrada acoplada a la salida del control automático de ganancia de transmisión y una salida acoplada al duplexor;y un detector de potencia acoplado y que ajusta el control automático de ganancia de recepción y al control automático de ganancia de transmisión en respuesta a una potencia detectada de la señal recibida.
- 13Un aparato para incrementar la inmunidad a la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal en una antena, el aparato comprende:un duplexor para separar una trayectoria de transmisión de una trayectoria de recepción, el duplexor acoplado a la antena;un amplificador de recepción de ganancia variable, en ia trayectoria de recepción, acoplado al duplexor para amplificar la señal recibida;un amplificador de transmisión de ganancia variable, en la trayectoria de transmisión, que tiene una entrada acoplada a una señal por transmitirse y una salida acoplada al duplexor;y un detector de potencia acoplado a y que ajusta el amplificador de recepción de ganancia variable y el amplificador de transmisión de ganancia variable en respuesta a una potencia detectada de la señal recibida.
- 14Un aparato para incrementar la inmunidad a -3333 la interferencia de radiofrecuencia de un radioreceptor, recibiendo el radioreceptor una señal en una antena, el aparato comprende:un atenuador variable acoplado a la antena;un duplexor para separar una trayectoria de transmisión de una trayectoria de recepción, el duplexor acopiado al atenuador de variable;un amplificador de recepción, en la trayectoria de recepción, acoplado al duplexor para amplificar la señal recibida;un amplificador de transmisión, en la trayectoria de transmisión, que tiene una entrada acoplada a una señal por transmitirse y una salida acoplada al duplexor;y un detector de potencia acoplado a y que ajusta el atenuador variable en respuesta a una potencia detectada de la señal recibida.
- 15Un circuito para incrementar la inmunidad de un radioteléfono a i;i interferencia de radiofrecuencia, teniendo dicho radioteléfono una antena para recibir y transmitir señales de radio y un duplexor acoplado a dicha antena, el circuito comprende:un amplificador de ganancia variable de recepción, acoplado a dicho duplexor, para amplificar dichas señales de radio recibidas, teniendo dicho amplificador de ganancia variable una entrada y una salida de ajuste de ganancia de recepción;un detector de potencia de recepción, que tiene una salida de ajuste de ganancia acoplada a dicha entrada de ajuste de ganancia de recepción y que tiene una entrada, dicho detector de -3434 potencia de recepción para detectar un nivel de potencia de dichas señales de radio recibidas y ajustar una ganancia de dicho amplificador de ganancia variable en respuesta a dicho nivel de potencie! detectado.
- 16El circuito según la reivindicación 15, caracterizado porque comprende además:un subconvertidor, acoplado a dicha salida amplificadora de ganancia variable de recepción, para subconvertir dichas señales de radio recibidas a partir de una radiofrecuencia hacia una frecuencia intermedia;un amplificador de ganancia variable frecuencia intermedia de recepción para amplificar dichas señales de radio subconvertidas para utilizarse en dicho radioteléfono;un amplificador de ganancia variable de frecuencia intermedia de transmisión, para amplificar una señal de frecuencia intermedia por transmitirse, teniendo una salida dicho amplificador de ganancia variable de frecuencia intermedia de transmisión;un sobreconversor, acoplado a dicha salida de dicho amplificador de ganancia variable de frecuencia intermedia de transmisión, para sobreconvertir dicha señal por transmitirse a partir de una frecuencia intermedia hacia una radiofrecuencia;y un amplificador de ganancia variable de transmisión, que tiene -3535 una salida acoplada a dicho duplexor, una entrada acoplada a dicho sobreconversor,, y una entrada de ajuste de ganancia de transmisión acoplada a dicha salida de ajuste de ganancia del detector de potencia de recepción, dicho amplificador de ganancia variable de transmisión para amplificar dicha señal sobreconvertida por transmitirse, teniendo dicho amplificador de ganancia variable de transmisión una ganancia que se ajusta mediante dicho detector de potencia de recepción en respuesta a dicho nivel de potencia detectado.
- 17El circuito según la reivindicación 16, caracterizado porque:dicha entrada del detector de potencia de recepción se acopla a dicha salida del amplificador de ganancia variable de frecuencia intermedia de recepción, dicho detector de potencia de recepción detectando dicho nivel de potencia de dichas señales de radio recibidas en dicha frecuencia intermedia;y dicho circuito comprende además un detector de umbral, que tiene una entrada de umbral acoplada a dicha salida de ajuste de ganancia del detector de potencia de recepción y una salida de umbral acoplada a dicha entrada de ajuste de ganancia de recepción y dicha entrada de ajuste de ganancia de transmisión, dicho detector de umbral para ajustar dicha ganancia de dicho amplificador de ganancia variable de recepción y dicha ganancia de dicho amplificador de -3636 ganancia variable de transmisión cuando dicho nivel de potencia detectado exceda un umbral predeterminado.
- 18El circuito según la reivindicación 16, caracterizado porque dicha entrada del detector de potencia de recepción se acopla a dicha salida del amplificador de ganancia variable de recepción, dicho detector de potencia de recepción detectando dicho nivel de potencia de dichas señales de radio recibidas en dicha radiofrecuencia.
- 19El circuito según la reivindicación 17, caracterizado porque comprende además un amplificador de ruido bajo, acoplado a dicho duplexor y dicho amplificador de ganancia variable de recepción e interpuesto entre los mismos, para amplifica;:dichas señales de radio recibidas.
- 20El circuito según la reivindicación 18, caracterizado porque comprende además un amplificador de ruido bajo, acoplado a dicho duplexor y dicho amplificador de ganancia variable de recepción e interpuesto entre los mismos, para amplificar dichas señales de radio recibidas.
- 21El circuito según la reivindicación 18, caracterizado porque comprende además un amplificador de ruido bajo, acoplado a dicho amplificador de ganancia variable de recepción y dicho subconversor e interpuesto entre los mismos, para amplificar dichas señales de radio recibidas.
- 22Un circuito receptor para incrementar la -3737 inmunidad de un radioteléfono a la interferencia de radiofrecuencia, teniendo dicho radioteléfono una antena para recibir y transmitir señales de radio, un duplexor acoplado a dicha antena, y un circuito de procesamiento de señal acoplado a dicho duplexor, el circuito receptor comprende:un amplificador de recepción que tiene una entrada y una salida, dicho amplificador de recepción para amplificar dichas señales de radio recibidas;una trayectoria de derivación, acoplada de manera conmutable a dicho amplificador de recepción, dicha trayectoria de derivación para atenuar una ganancia de dicho amplificador de recepción cuando se encuentra en una posición de derivación;y un controlador acoplado a dicha trayectoria de derivación, para conmutar dicha trayectoria de derivación a dicha posición de derivación cuando un nivel de potencia detectado de dichas señales de radio recibidas excede un umbral predeterminado.
- 23El circuito receptor según la reivindicación 22, caracterizado porque dicha trayectoria de derivación comprende un primer conmutador que tiene un entrada acoplada a dicho duplexor, y que tiene una posición en serie, una posición de derivación, y una salida, acoplándose dicha primer salida del conmutador a dicha entrada del amplificador de recepción cuando dicho primer conmutador se encuentra en dicha posición en serie y -3838 acoplándose dicha primer salida del conmutador a una entrada de un segundo conmutador cuando dicho primer conmutador se encuentre en dicha posición de derivación, teniendo dicho segundo conmutador una salida acoplada a dicho circuito de procesamiento de señal, y que tiene una posición en serie y una posición en derivación, acoplándose dicha segunda entrada del conmutador a dicha salida del amplificador de recepción cuando dicho segundo conmutador se encuentra en dicha posición en serie y acoplándose dicha segunda entrada del conmutador a dicha primera salida del conmutador cuando dicho segundo conmutador se encuentra en dicha posición de derivación.
- 24El circuito según la reivindicación 22, caracterizado porque dicha trayectoria de derivación comprende un conmutador que tiene una entrada acoplada a dicho duplexor y que tiene una salida acoplada a dicha salida del amplificador de recepción cuando dicha trayectoria de derivación se encuentra en dicha posición de derivación.
- 25El circuito según la reivindicación 22, caracterizado porque dicha trayectoria de derivación comprende un conmutador que tiene una salida acoplada a dicho circuito de procesamiento de señal, y que tiene una entrada acoplada a dicha entrada del amplificador de recepción cuando dicha trayectoria de derivación se -3939 encuentra en dicha posición de derivación.
- 26El circuito según la reivindicación 22, caracterizado porque dicha trayectoria de derivación comprende una carga conmutable que tiene una salida acoplada a un potencial de tierra y que tiene una entrada acoplada a dicha entrada del amplificador de recepción cuando dicha trayectoria de derivación se encuentra en dicha posición de derivación.
- 27Un método para incrementar la inmunidad de un radioteléfono a la interferencia de radiofrecuencia, teniendo dicho radioteléfono una antena para recibir señales de radio que tienen un nivel de potencia recibida, un atenuador, un amplificador de recepción de ganancia variable, un controlador de ganancia, y un detector de potencia de recepción, el método comprende las etapas de:dicho controlador de ganancia varia dicho nivel de potencia recibido de dichas señales de radio recibidas en una cantidad predeterminada;dicho detector de potencia de recepción detecta un cambio en dicho nivel de potencia recibida de dichas señales de radio recibidas;y dicho controlador de ganancia ajusta una ganancia de dicho amplificador de recepción de ganancia variable en respuesta a dicho cambio de nivel de potencia recibido detectado.
- 28El método según la reivindicación 27, caracterizado porque dicha etapa de variación comprende la -4040 atenuación de dichas señales de radio recibidas con dicho atenuador de variable.
- 29El método según la reivindicación 27, caracterizado porque dicha etapa de variación comprende el 5 ajuste de dicha ganancia de dicho amplificador de recepción de ganancia variable.
- 30El método según la reivindicación 28, caracterizado porque dicha etapa de ajuste comprende además:disminuir dicha ganancia de dicho amplificador de io recepción de ganancia variable cuando dicho cambio de nivel de potencia recibido detectado es mayor a un umbral predeterminado;e incrementar dicha ganancia de dicho amplificador de recepción de ganancia variable cuando dicho cambio de nivel de potencia recibido detectado es menor o 15 igual a un umbral predeterminado.
- 31El método según la reivindicación 29, caracterizado porque dicha etapa de ajuste comprende además:disminuir dicha ganancia de dicho amplificador de recepción de ganancia variable cuando dicho cambio de nivel 20 de potencia recibido detectado es mayor a un umbral predeterminado;e incrementar dicha ganancia de dicho amplificador de recepción de ganancia variable cuando dicho cambio de nivel de potencia recibido detectado es menor o igual un umbral predeterminado. -4141
Independent claims31
176 paragraphs in 12 sections, as filed
Pl'T WORLD INTELLECTUAL PROPERTY OROANIZATION * ^ · * · biterealional Buresu
INTERNATIONAL APPUCATION PUBUSHED UNDER THE PATENT COOPERATION TREATY (PCT) (SI) International Patent Claasillcation 6 <sub>:</sub> (11) International Publication Number; WO 96/19048
H04B7AD05
A3 (43) International Publication Date:
June 1996 (20.06.96) (21) International AppUcatioa Number: PCT / US9S / 16002 (22) International FBlng Date: 11 December 1993 (11.12.93) (30) Prlority Dala:
357,951 16 December 1994 (16.12.94) US
522,467 31 August 1995 (31.08.95) US (71) AppUcant: QUALCOMM INCORPORATED [US / US); 6455
Lusk Boulevard, San Diego, CA 92121 (US).
(72) Inventor: WHEATLEY. Charlea, E „ΠΙ; 2208 Caminito Del
Barco, Del Mar, CA 92014 (US). PETERZELL, Paul. AND.; 6146 Calle Mariaelda # 203, San Diego, CA. 92124 (US). KORNFELD, Richard, Κ .; 12384 BrickellH Street San Diego. CA 92129 (US). WE1LAND, Ana. I ..; 2042 Sheridan Roed, Encintas, CA 92024 (US).
(74) Agent: M1LLER, Rusaell, B .; Qualcomm locorporated. 6455 Lusk Boulevard. San Diego, CA 92121 (US).
(81) Deaignated States: AL, AM. AT, AU, BB, BG. BR. BY, CA. CH, CN. CZ, DE, DK, EE, ES. Fl, GB. GE, HU, IS. JP. KE, KG, KP, KR. KZ, LK, LR, LS. LT. LU, LV, MD, MG, MK, MN. MW, MX, NO, NZ, PL, PT, RO, RU. SD, SE. SG, SI, SK. TJ, TM, TT, UA UG, UZ, VN, European patent (AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE). OAPI patent (BF. BJ, CF, CG, CI . CM. GA, GN, ML, MR, NE, SN, TD, TG), ARITO patent (KE, LS. MW. SD, SZ. UG).
PubUabod
WiA international tearch repon.
Before Ae expired * of Ae lime limit for amending Ae claimt and lo be rt pubíitbed in Ae event of the receipt of amendmentt.
(IS) Date ot publicatloa ot the latsraathmal aaarch report:
September 1996 (06.09.96) (34) Tltle: METHOD AND AFPARATUS FOR INCREASING RECEIVER IMMUNITY TO INTERFERENCE
<img file="MX9704445A_D0001.tif" />
(57) Abatract
The method and apparatua of the preaent invention improve the immunity to interference of a radio receiver. The power level of a teceived aignal is delected. If the power leve) meeta or eaceeda a predetermined power thrcahold, the low noise amplifier (703) is by-passed (730), tbua incrcaaing the intercept point of the raceiver component. Altemative performances inelude the use of an RF power detector (105) to control the front-end gain (110) at a function of Jnmmer power. In li eu of a iwitchable RF gain block (730). several methods of continuoua gain control are proposed. Continuous gain control allowj the interference supprcasion and sensitivity of the receiver to be adjusted at lower ligua! levelj than the iwitchable gain block. A method of the preaent invention attached the input gain by a predetermined amount (1601). The receiver Processing measurei the gain ctange in the IF aignal power (1605). Ifthechange is lesa than the predetermined amount (1610). the CDMA aignal and jammers are below the noise lloorand, therefore. the gain is increased (1615). If the IF signa) power change is greater than the predetermined amount, the interference ia evident and the gain ia reduced to reduce the imermodulation producís (1620). Thia procesa ia used until the receiver is operating ai: the bett compromise between interference and noise figure.
I'rinted from Mimosa
METHOD AND APPARATUS TO INCREASE IMMUNITY
AT THE INTERFERENCE OF A RECEIVER
BACKGROUND OF THE INVENTION
I. FIELD OF THE INVENTION
The present invention relates to radio communications. More particularly, the present invention relates to enhancing immunity to interference from a communication receiver.
II. DESCRIPTION OF RELATED MATTER
There are currently multiple types of operating cellular radiotelephone systems. These systems include Advanced Mobile Telephone System (AMPS) and two-digit cellular systems: Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). Digital cellular systems are implemented to handle capacity problems experienced by AMPS.
All cellular radiotelephone systems operate by having multiple antennas that cover a geographic area. The antennas radiate to an area referred to in matter as a cell. AMPS cells are separated and distinguished from CDMA cells. This makes it probable that the antenna for one cell in the system can be located in a cell in another system. Similarly, within a particular system (AMPS, CDMA, and TDMA), there are two service providers within a given area. These providers often choose to place the cells in different geographic locations from their competitor, therefore there are situations where a radiotelephone in the system Ά 'could be quite far from the cell
Del 'of the closest system while being near a cell of the' B 'system. This situation means that the desired reception signal will weaken in the presence of strong multi-tone interference.
This intermixing of system antennas can cause problems for a mobile radiotelephone that registers with a system, such as the CDMA system, and travels close to another antenna in the system, such as an AMPS antenna.
In this case, signals from the AMPS antenna may interfere with CDMA signals received by the radiotelephone due to the proximity of the radiotelephone to the AMPS cell or the increased power of the AMPS forward link signal.
The multi-tone interference found by the radiotelephone from AMPS signals creates distortion products or leads. If these leads fall into the CDMA band used by the radiotelephone, they may degrade receiver performance and long-term demo.
The case is frequently where an AMPS system for vehicles (bands A and B) 'unintentionally' disturbs' the competing system. The purpose of the cellular vehicle is to provide a high signal-to-noise ratio to all users of its system by placing cells close to the ground, or close to their users, and irradiating the FCC power limit for each channel of
AMPS. Unfortunately, this technique provides better signal quality to the vehicle's system at the cost of interfering with the competitor's system.
Intermodulation distortion, such as that caused by the above situations, is defined in terms of the peak parasitic level generated by two or more tones injected into a receiver. Most frequently, the third order distortion level is defined for a receiver in terms of a third order input intercept point, or IIP3. IIP3 is defined as the input power (in the form of two tones) required to create third order distortion products equal to the tone power of two inputs. As shown in Figure 13, IIP3 can only be extrapolated linearly when a nonlinear element, such as an amplifier, is below saturation.
As shown in Figure 14, third order distortion products occur when two tones are injected into a receiver. Tone # 1 is found on the frequency fl at a power level Pl in dBm. Tone # 2 is on a frequency f2 at a power level P2 in dBm. Typically P2 is set equal to Pl. Third order distortion products will be created at frequencies 2xfl - f2 and 2xf2 - fl at power levels P12 and P21, respectively. If P2 is set equal to Pl, then the parasitic products must be equal, or P12 and P21 must be equal. The faith signal is injected at a io power level Pe to demonstrate that the added distortion equals a low level signal in this case. If there is a filter that filters fl, f2, and f21 after the distortion is created, the power in fl2 will interfere with the signal power in fe. In the example in Figure 14, for a CDMA application, the purpose is that P12 intermodulation must equal the signal power of -105 dBm for a total two-tone power of -43 dBm, so IIP3 it must be> -9 dBm.
As is well known in the art, the IIP3 for a single non-linear element is defined as the following:
IM3
IIP3 = - ^ - + P<sub>in</sub>(dBm) siPi = P<sub>2</sub>, Then p<sub>in</sub> = Pi + 3 dB or P<sub>2</sub> + 3 dB (dBm) and
IM3 = Pi - Pi<sub>2</sub> = P<sub>2</sub> - P<sub>2</sub>i = P<sub>2</sub> - P12 = Pi ~ P21 (dB)
For cascaded IIP3, where more nonlinear elements are used, the equation is as follows:
jjp3 __] _ Q * j_<sub>OR</sub>g | 0 [10 <sup>(gain</sup>'<sup>element</sup>° <sup>eleven P3</sup>1/1 ° ^. ] _ Q ("I<sup>1</sup> P3 <sup>from Pas</sup> previous stages) / 10j where: gain = gain for the input of the element.
Therefore, one way to improve the IIP3 of a cascaded receiver is to decrease the gain before the first nonlinear element. In this case, the LNA and the mixer limit IIP3. However, another quantity needs to be defined that establishes the sensitivity or the lower level of the reception signal without interference, io This quantity is referred to in the matter as the noise figure (NF). If the receiver gain is reduced to improve IIP3 (and immunity to interference), NF (and the sensitivity to small desired signals) is degraded.
The NF element is defined as the following:
H.H
ElementNF = ——— (dB),
Ni N<sub>or</sub>
<td></td><td>in</td><td>where</td><td>one Neither</td><td>is</td><td>the proportion</td><td>of</td><td>signal input</td><td>to</td>
<td>noise</td><td>in dB,</td><td>and</td><td>N<sub>or</sub></td><td>is</td><td>the proportion</td><td>of</td><td>signal output</td><td>to</td>
<td>noise</td><td>in dB.</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>
<td> 20</td><td colspan="2">For the</td><td colspan="3">cascading elements</td><td>in</td><td>a receiver,</td><td>the</td>
equation is as follows:
Cascaded NF = 10 * logl0 [10 (Nfi / 10) lQ (NFe / 10) (Gain / 10) where: NFe equals the noise figure of the element,
NFi equals the cascading noise figure to the element, and the Gain equals the execution gain to the element.
The 'best' NF cascading can be achieved if the gain is maximized to the element, this equation is in contradiction to the requirement for the 'best' IIο IIP3 cascading. For, an element given by the element and the receiving NF and IIP3, there is a set of limited gain values for each element that meets all requirements.
Typically, a receiver is designed with NF and IIP3 15 as predefined constants, since both of these quantities establish the dynamic operating range with and without interference of the receiver. The gain, NF and IIP3 of each device is optimized based on size, cost, thermal current, static and active element current consumption. For a dual-mode portable CDMA / FM cellular receiver, the CDMA standard requires a 9 dB NF at a minimum signal. In other words, for CDMA mode, the sensitivity requirement is a ratio of 0 dB S / N to -104 dBm.
For FM mode, the requirement is a ratio of 4 dB S / N to -116 dBm. In both cases, the requirements can be translated into NF as follows:
S
NF = S (dBm) - (dB) -N<sub>technical</sub> (dBm / Hz) - BW signal (dB / Hz),
N where S is the minimum signal power,
S - is the minimum signal-to-noise ratio N
Thermal is the floor of thermal noise (-174 dBm / Hz @
290 ° K), and the BW Signal (dB / Hz) is the bandwidth of the signal.
Therefore,
CDMA NF = -104 dBm -0 dB - (-174 dBm / Hz) - 61 dB / Hz = 9 dB,
FM NF = -116 dBm -4 dB - (-174 dBm / Hz) -45 dB / Hz = 9 dB,
<td></td><td>where -61 dBm / Hz is</td><td>the</td><td>amplitude</td><td>of</td><td>band</td><td>of</td><td>noise</td>
<td>for</td><td>a CDMA channel.</td><td></td><td></td><td></td><td></td><td></td><td></td>
<td></td><td>-45 dBm / Hz is</td><td>the</td><td>amplitude</td><td>of</td><td>band</td><td>of</td><td>noise</td>
<td>for</td><td>an FM channel.</td><td></td><td></td><td></td><td></td><td></td><td></td>
<td> 20</td><td>However the</td><td>NF</td><td>receiver</td><td>only</td><td>I know</td>
<td>requires</td><td>when the signal</td><td>I know</td><td colspan="3">located near the level</td>
<td>minimum and</td><td>IIP3 only</td><td>I know</td><td>requires in the</td><td>presence</td><td>of</td>
interference or strong CDMA signals.
There are only two ways to provide coverage in areas where the vehicle is located creating strong interference. One solution is to use the same technique; that is, co-locate their cells along with those of the competition. Another solution is to improve a recipient's immunity to interference. One way to improve immunity is to increase the receiving current. However, this is not a practical solution, for a portable radio that depends on the power of the battery. Increasing the current would drain the battery more quickly, thereby decreasing the talk time and wait for the radiotelephone. There is a resulting need to minimize multi-tone interference to a radiotelephone without impacting current consumption.
SUMMARY OF THE INVENTION
The process of the present invention adjusts the attenuation in a circuit, thereby improving a receiver's immunity to interference. The circuit has an attenuator with attenuation and automatic gain control (AGC) with variable gain. The process varies the attenuation by a predetermined amount. The gain of the circuit is then detected. If the detected gain change is greater than a predetermined threshold, intermodulation products have been detected and the front end attenuation is increased to reduce the power of the intermodulation product.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a block diagram of the apparatus of the present invention to increase the immunity of the recipient.
Figure 2 shows a block diagram of another alternate embodiment of the present invention.
Figure 3 shows a block diagram of another alternate embodiment of the present invention.
Figure 4 shows a block diagram of another alternate embodiment of the present invention.
Figure 5 shows another graph of received RF input power versus vehicle-to-noise ratio according to the mode of figure 7.
Figure 6 shows a graph of reception RF input power versus vehicle-to-noise ratio according to the mode of Figure 8.
Figure 7 shows a block diagram of another alternate embodiment of the present invention.
Figure 8 shows a graph of interference power versus signal power without using the apparatus of the present invention.
Figure 9 shows a graph of interference power versus signal power according to the
-1010 alternate embodiments of the apparatus of the present invention.
Figure 10 shows a block diagram of an alternate embodiment of the present invention.
Figure 11 shows a block diagram of another alternate embodiment of the present invention.
Figure 12 shows a block diagram of another alternate embodiment of the present invention.
Figure 13 shows a graph of nonlinear transfer characteristics and distortion measurement.
Figure 14 shows a spectral description of distortion products.
Figure 15 shows a block diagram of a method for detecting the power of a received signal in accordance with the present invention.
Figure 16 shows a flow diagram of the attenuation control process of the present invention.
DESCRIPTION OF THE PREFERRED MODALITY
An objective of the present invention is to vary the NF and IIP3 of the receptor to improve IIP3 (or immunity to interference) without compromising the NF when necessary). This 'enhancement' of performance is accomplished by varying the gain of the first active element in the receiver. The gain may vary by varying the LNA gain over a continuous range or switching the
-1111 low noise amplifier with bypass switches.
A block diagram of the preferred embodiment of the present invention is illustrated in Figure 1. This embodiment involves adjusting the gain of the LNA 115 on a continuous basis using the adjustable gain control (AGC) 110 at the front end of the receiver. The continuous AGC 110 at the front end also provides a linearity benefit at a minimum RF input level while the AGC 120 on the transmission side can reduce the SI requirements of the AGC 125 and 130.
This mode detects the power output of the
LNA 115. Power detector 105 measures both the signal power and the disturbance power together in the RF. Using this mode, the power detector 105 can continuously decrease the gain of the
LNA 115 at a received power less than -65 dBm from the subsequent switched gain modes of Figures 7, 10, 11, and 12 ..
The preferred embodiment operates by means of the power detector 105 that detects the signal and disturbance power received in the RF. This sensed power goes through a cycle filter and is used to adjust the receive AGC 110, thereby adjusting the point of intersection of the receive components. The gain is decreased as the measured power is
-1212 increases and the gain increases as the measured power decreases. This modality could also combine LNA 115 and AGC 110 to form a variable gain LNA, thus eliminating the need for a separate block of AGC 110. The power of the transmit AGC
120, located before the power amplifier 150, is adjusted in the same manner as the receive AGC 110 in order to maintain the total TX power level.
The AGC 125 and 130 amplifiers are also located after mixers 135 and 140 in order to adjust the gain after the disturbers have been filtered out by bandpass filter 145. These AGC 125 and 130 amplifiers carry Perform normal CDMA AGC function of open cycle power control, closed cycle power control, and compensation. These IF 125 and 130 AGCs are needed due to the requirements of a wide dynamic range for CDMA. Typically, these 125 and 130 AGCs have a gain range greater than 8 0 dB. The transmit and receive AGC 125 and 130, after the mixers are adjusted by another power detector 150 measure the total power after the received signal is sub-converted. Power detector 150 adjusts the gain of AGCs 125 and 130 downward as the power of the subverted signal increases
-1313 and adjusts the gain of AGCs 125 and 130 upward as the subverted signal power decreases.
In the preferred embodiment, the received signals are in the 869-894 MHz frequency band.
The transmitted signals are in the 824-849 MHz frequency band. Alternate modes use different frequencies.
The graph illustrated in Figure 5 shows the benefit of this AGC approach. The y-axis to the left shows the ratio of vehicle to noise versus receive input power parameterized by the disturbance level. The y-axis to the right shows the total interfering emitting power required for a constant C / J as a function of received input power. When the disturber is not present (-100 dBm), the radio operates as if there is no RF AGC. As the disturber increases, the C / N decreases, but the effective linearity also increases. In this example, the dynamic range of RF is 30 dB and the threshold,
<td>where</td><td>the</td><td>AGC</td><td>of</td><td>RF turns</td><td>active,</td><td>I know</td><td>found in</td><td>the</td>
<td>point</td><td>in</td><td>than</td><td>the</td><td>power of</td><td colspan="2">disturbing</td><td>is greater than</td><td> -25</td>
<td>dBm.</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>
<td></td><td></td><td>A</td><td colspan="3">alternate mode of</td><td colspan="2">continuous adjustment</td><td>of</td>
gain is illustrated in figure 2. This modality separates
1414 first by filtering the disturbers with the bandpass filter 205 before the power detector 210 determines the power level of the converted signal.
A threshold detector 225 determines when the signal power level reaches a certain point, -105 dBm in this mode, and then adjusts the gain of the AGCs 230 and
235 below when the signal power exceeds that power level. The gain of AGCs 230 and 235 is adjusted upward when the signal power level goes below this threshold. The gain of AGCs 215 and 220 after mixers 240 and 245 is continuously adjusted without checking the predetermined power threshold, performing power control of
Normal CDMA AGC.
The graph of this mode is illustrated in Figure 6. When the threshold is set to -105 dBm, the minimum receive RF level, the C / N does not increase as rapidly as in the case where there is no RF AGC.
The advantage of this mode is that the linearity benefit starts at each low RF input power, no receiving RF power detector is needed, and the AGC cycle detects only the signal power. However, the AGC cycle is a simpler design than detection at RF power.
Still another embodiment of the present invention
-1515
<td>illustrated</td><td>in</td><td>the figure</td><td colspan="2">3. This modality</td><td>Opera</td><td>of</td><td>way</td>
<td>similar to</td><td>the</td><td>modality</td><td>of the figure</td><td> 1.</td><td>Being</td><td>the</td><td>only</td>
<td>difference</td><td>the</td><td>placement</td><td>AGC 301</td><td>before</td><td colspan="2">of the LNA</td><td>305 in</td>
the receiving path.
Yet another embodiment of the present invention is illustrated in FIG. 4. This embodiment uses an attenuator 405 between antenna 410 and duplexer 415. Attenuation is controlled by power detector 420 after LNA 425. Power detector 420 measures the received signal and disturbance power filters them and compares them to a predetermined threshold. In this mode, the threshold is -25 dBm. When the combined signal and disturbing power reach this threshold, the attenuation caused by attenuator 405 is increased. This adjustment can be either in digital fixed stages or continuously adjusted. AGC 430 and
435 after mixers 440 and 445 it is set in the same way as the preferred embodiment of figure 1.
An alternate mode of the apparatus of the present invention is illustrated in Figure 7. This mode uses switches 701 and 702 to alter the front end gain. The actual switching level depends on the signal-to-noise requirements as a function of the signal level, or the noise figure, for a particular CDMA radiotelephone design. The present
The invention can be used in an AMPS radiotelephone, however, the switching characteristics will change to accommodate a different point of operation.
This modality comprises an antenna 725 that receives and transmits radio signals. The radio receive and transmit paths are coupled to antenna 725 through a duplexer 720 that separates the received signals from the transmitted signals.
A received signal is input to an LNA 703 that is coupled between two switches 701 and 702. A switch
701 couples the LNA 703 to the duplexer 720 and the second switch 702 couples the LNA 703 to a bandpass filter 704. In the preferred embodiment, the switches 701 and 702 are single pole, two-way gallium arsenide switches.
LNA 703 is coupled to one pole of each switch such that when both switches 701 and 702 are switched to those poles, the received signal is coupled to the LNA
703 and the amplified signal from the LNA 703 is output to the bandpass filter 704. The bandpass filter
704 in this mode it has a frequency band of 8 69894 MHz. Alternate modes use different bands depending on the frequencies of the signals being received.
A bypass path 730 couples to the
-1717 another pole of each switch. When switches 701 and 702 are switched to their other poles, the signal received from duplexer 720 bypasses LNA 703 and is routed directly to bandpass filter 704. In this mode, these switches 701 and 702 are controlled by the 740 radiotelephone microcontroller. In an alternate mode, a separate controller is used to control the positions of these switches.
After the bandpass filter 704 has filtered the received signal, the filtered signal is converted to a lower intermediate frequency (IF) for use by the rest of the radio. The sub-conversion is done by mixing the received signal in 705 with another signal that has a frequency set by a phase locked circuit 707 that drives a voltage controlled oscillator 706. This signal is amplified by 750 before being fed into mixer 705.
The converted signal from mixer 705 is input to the rear end AGCs 708 and 709. These AGCs 708 and 709 are used by the radiotelephone for closed loop power control, as is already well known in the art.
In the process of the present invention, the 740 microcontroller monitors the power of the received signal. When the power exceeds -65 dBm, the
-1818 Microcontroller 740 instructs switches 701 and 702 to switch to the bypass position, thereby coupling the received signal directly to bandpass filter 704.
By deriving the gain from LNA 703, the intercept point for the receiver is increased proportionally by reducing the gain in dB. Alternate modes use other circuitry and methods to monitor the strength of the received signal.
An alternate embodiment of the process of the present invention continuously adjusts the front end gain. This mode uses a lower power threshold such as -25 dBm.
The graphs of Figures 8 and 9 illustrate the benefits of the switchable gain modes of the present invention illustrated in Figures 7, 10, 11 and
12. Figure 8 illustrates a graph of interference power versus radio frequency (RF) signal power for a typical radio that does not use the switchable gain apparatus. This graph shows that the maximum interference level is limited to the receiver's input compression point at -10.5 dBm. Both single and dual tone power curves are shown.
The graph in Figure 9 shows the interference power received by the radio versus the power of
-1919 radio frequency signal received by the radio using the switchable gain method and apparatus of the present invention. It can be seen that at the -65 dBm point of the graph, the switches are switched to derive the LNA gain, thus allowing higher interference power to be tolerated without affecting the RF signal power. Single-tone and two-tone curved power shafts are shown.
Another alternate embodiment of the apparatus of the present invention is illustrated in FIG. 10. This mode uses a single-pole, single-pole switch 1001. In this mode, switch 1001 is switched to bypass path 1010 by controller 1020 when the received signal power reaches -65 dBm. This effectively shortens the gain of the
LNA 1002 thus coupling the received signal directly to the bandci 1003 pass filter.
Yet another alternate embodiment of the apparatus of the present invention is illustrated in FIG. 11. This embodiment utilizes a single-pole, single-pole switch 1005 which, when closed, shortens the LNA 1110 input to the floor via a 1101 resistor. This creates an input impedance comparison error that causes the signal to attenuate, thus reducing the gain caused by the LNA 1110. As in the modes
-2020 above, the 1105 switch closes when the input signal power reaches -65 dBm. The resistance required for resistor 1101 depends on the amount of attenuation desired. This resistance will be different for the different LNAs in the alternative modalities.
Still another embodiment of the apparatus of the present invention is illustrated in FIG. 12. This embodiment utilizes a single pole double direction switch,
1201 at the output of LNA 1205. LNA 1205 is connected to one pole of switch 1201 and a bypass path 1210 is connected to the other pole. The bypass path input 1210 connects to the input of the
LNA 1205. When the power level of the received RF signal reaches -65 dBm, switch 1201 is routed from the coupling position of LNA 1205 to bandpass filter 1220 toward bypass path 1210.
This couples the signal directly to the bandpass filter 1220, deriving the gain from the LNA 1205.
In all of the above modes, the LNA can be de-energized while being bypassed by the switch or switches. This is done by connecting the LNA · power terminal to a switch that is also controlled by the controller. Once the LNA is bypassed and no longer used, the power can be withdrawn. This reduces the power consumption of the radio,
-2121 thus increasing the talk and standby time for which the battery can be used.
In another embodiment of the present invention, detection E<sub>c</sub>/ I<sub>0</sub> used to determine when to adjust the front end gain. Additional modalities use other quality measurements, such as
AND<sub>b</sub>/ Io.
These ratios are quality measurements for the performance of the digital communications system. The proportion E<sub>b</sub>/ I<sub>or</sub> expresses the energy per bit for the total interference spectral density of the channel while the proportion E<sub>c</sub>/ I<sub>or</sub> expresses the energy per microcircuit of CDMA in relation to the total interference spectral density. The e<sub>b</sub>/ I<sub>or</sub> it can be considered a metric that characterizes the performance of one communication system over another; the smaller the E<sub>b</sub>/ I<sub>or </sub>required, the more efficient the system detection and modulation process is for a given probability of error. Since E<sub>c</sub>/ I<sub>0</sub> and the received signal resistance are readily available, the microcontroller can detect the presence of strong interference such as a drop in
AND<sub>c</sub>/ I<sub>or</sub> while the AGC detector detects the increased interference. The microcontroller can decrease front end gain to improve immunity to interference, which would improve E<sub>c</sub>/ I<sub>or</sub> and it would decrease
-2222 distortion products that fall within the bandwidth of the signal.
When the signal quality goes above the threshold of E<sub>b</sub>/ I<sub>or</sub> or of E<sub>c</sub>/ I<sub>or</sub>, the front end gain is reduced. The gain adjustment can be carried out using either the continuous adjustment method or the amplifier switching method, both described above.
Still another embodiment, illustrated in Figure 15, would detect IF or baseband signal power instead of the combination of signal power and RF disturbance. This approach is simpler since there is only one power detector and one AGC control cycle.
Figure 15 illustrates a block diagram of the alternate method for detecting the received signal strength. The signal is first converted to a baseband frequency 1501. This analog signal is then converted to a digital signal 1505 for further baseband processing including determination of the received signal resistance. The microcircuit correlate 1510 determines the energy per microcircuit with respect to the energy of all non-coherent components. This information, together with the received signal resistance indicator (RSSI) is
-2323 used by processor 1515 to determine the amount of gain adjustment for both receive powers
1520 and transmission 1530.
Since the received signal power measurement includes both signal and disturbance powers, the receive gain increases only when both the signal level and the microcircuit energy drop. Since the RSSI is being changed, the transmit power must also be changed io to compensate, thus allowing the open cycle power control to operate properly. In this way, the processor adjusts the transmit gain as long as the receive gain is adjusted.
Other modes use erase or signal power to control the variable gain AGC. The additional modes, instead of controlling both transmit and receive powers, only control the receiving power.
Figure 16 illustrates a process for controlling the gain of the above modes. This process is based on the relationship illustrated in the graph in Figure 13. In Figure 13, one can observe that as the interference input power increases along the X axis, the intermodulation products (the curve lower) increases more
-2424 faster than interference power. Therefore, X dB of attenuation applied to the input will result in a decrease of the IM3 intermodulation products by 3 * X dB if the interference occurs at the receiver input.
Typically, the intermodulation products do not fall into the IF section of the radio due to their low power. Intermodulation products outside the IF section of the radio do not cause performance problems for the receiver. In this way, adjustment of the receiver gain is only necessary if the intermodulation products are of sufficient power to affect the IF signal.
Referring to Figure 16, the process of the present invention first adjusts the input gain 1601. In the preferred embodiment, this gain adjustment is 3 dB. However, other modes may use other gain adjustment values, such as the 1 dB - 6 dB range. Receiver processing is then used to measure the change in received signal power 1605. In the preferred embodiment, automatic gain control processing detects the change in power of the IF signal. It is understood that the measurement of the change in received signal power can also be carried out in the RF or baseband stages of the
-2525 receiver.
If the signal strength changes by approximately 3 dB, the CDMA signal is higher than the noise floor and there is no intermodulation product that could cause problems. Additional qanance adjustment is not necessary in this case, but increasing the qanance will improve receiver sensitivity. IF signal power changes of approximately (3 + 0.5) dB are still considered to be 3 dB.
If the IF signal strength changes by less than 3 dB 1610, the CDMA signal is less than the noise floor, or there are no intermodulation products that could cause problems. In this case, the AGC is observing only a small CDMA signal and noise. Accordingly, it is necessary to increase the gain of the receiver circuit 1615 and thereby increase the sensitivity of the receiver.
If the IF signal power changes by more than 3 dB, the intermodulation products cause sufficient problems, requiring an additional 1620 gain adjustment. In the preferred mode, if the input gain was changed by 3 dB, the products of Intermodulation will change by 9 dB when heavy interference occurs. In this case, the average profit can be decreased by a small amount (for example, 3
-2626 dB) until the process of the present invention determines that the intermodulation products are reduced to an acceptable level.
The process of the present invention can be used continuously, checking the intermodulation products at a low speed. This speed is 10 times per second in the preferred mode. Other modalities use the process once per structure cycle. Still other modes use the io process at other speeds, such as after detection of a significant forward link error.
In summary, the method of the present invention allows a mobile radio to travel to nearby antennas of different systems while increasing the resistance of
<td>15 spokes</td><td>to</td><td>the</td><td>interference</td><td>of</td><td colspan="2">radiofrequency</td>
<td>coming</td><td>of</td><td>the</td><td>other systems.</td><td></td><td>By decreasing</td><td>the</td>
<td>profit of</td><td colspan="2">extreme</td><td>front point</td><td>of</td><td>intersection</td><td>of</td>
the radio reception circuitry is increased so that the derivations coming from the signals of the other system do not cause degradation of receiver and demodulator performance.
-2727
Contents12
15 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7 Sheet 8 Sheet 9 Sheet 10 Sheet 11 Sheet 12 Sheet 13 Sheet 14 Sheet 15
116 members in 23 offices
Priority claims3
| Document | Office | Kind | Date |
|---|---|---|---|
| 35795194 | United States of America | A | |
| 52246795 | United States of America | A | |
| 9516002 | United States of America | W |
Members116
| Document | Office | Kind | |
|---|---|---|---|
| IL116364D0 | Israel | D0 | |
| ZA9510321B | South Africa | B | |
| CA2207745A1 | Canada | A1 | |
| CA2467276A1 | Canada | A1 | |
| CA2467295A1 | Canada | A1 | |
| WO9619048A2 | World Intellectual Property Organization (WIPO) | A2 | |
| AU4419696A | Australia | A | |
| WO9619048A3 | World Intellectual Property Organization (WIPO) | A3 | |
| TW301826B | Taiwan Province of China | B | |
| AR000363A1 | Argentina | A1 | |
| FI972501A | Finland | A | |
| FI972501A7 | Finland | A7 | |
| MX9704445AThis record | Mexico | A | |
| EP0797873A2 | European Patent Office (EPO) | A2 | |
| US5722061A | United States of America | A | |
| US5722063A | United States of America | A | |
| CN1175329A | China | A | |
| US5732341A | United States of America | A | |
| KR980700738A | Republic of Korea | A | |
| JPH10510965A | Japan | A | |
| BR9510050A | Brazil | A | |
| HK1004453A1 | Hong Kong, China | A1 | |
| AU703393B2 | Australia | B2 | |
| FI990710A | Finland | A | |
| FI990710A7 | Finland | A7 | |
| NO991578D0 | Norway | D0 | |
| AU1424799A | Australia | A | |
| AU1424899A | Australia | A | |
| AU1424999A | Australia | A | |
| AU1425099A | Australia | A | |
| NO991578L | Norway | L | |
| CA2275115A1 | Canada | A1 | |
| WO9929047A1 | World Intellectual Property Organization (WIPO) | A1 | |
| AU4735697A | Australia | A | |
| US5930692A | United States of America | A | |
| AU717774B2 | Australia | B2 | |
| AU717794B2 | Australia | B2 | |
| AU717843B2 | Australia | B2 | |
| EP1020041A1 | European Patent Office (EPO) | A1 | |
| KR20000049037A | Republic of Korea | A | |
| IL131443D0 | Israel | D0 | |
| JP2001505026A | Japan | A | |
| IL129261D0 | Israel | D0 | |
| IL116364A | Israel | A | |
| HK1031280A1 | Hong Kong, China | A1 | |
| AU742121B2 | Australia | B2 | |
| BR9712974A | Brazil | A | |
| JP2002190748A | Japan | A | |
| CN1090847C | China | C | |
| RU2196384C2 | Russian Federation | C2 | |
| CN1396721A | China | A | |
| KR100369272B1 | Republic of Korea | B1 | |
| RU2211532C2 | Russian Federation | C2 | |
| IL129261A | Israel | A | |
| IL131443A | Israel | A | |
| RU2002125369A | Russian Federation | A | |
| EP1020041B1 | European Patent Office (EPO) | B1 | |
| AT264028T | Austria | T | |
| ATE264028T1 | Austria | T1 | |
| DE69728573D1 | Germany | D1 | |
| KR100432209B1 | Republic of Korea | B1 | |
| JP2004166307A | Japan | A | |
| MY117285A | Malaysia | A | |
| DK1020041T3 | Denmark | T3 | |
| EP0797873B1 | European Patent Office (EPO) | B1 | |
| AT274260T | Austria | T | |
| ATE274260T1 | Austria | T1 | |
| DE69533405D1 | Germany | D1 | |
| CA2207745C | Canada | C | |
| ES2222502T3 | Spain | T3 | |
| EP1503517A2 | European Patent Office (EPO) | A2 | |
| EP1503517A3 | European Patent Office (EPO) | A3 | |
| EP1513268A2 | European Patent Office (EPO) | A2 | |
| ES2225851T3 | Spain | T3 | |
| EP1513268A3 | European Patent Office (EPO) | A3 | |
| DE69728573T2 | Germany | T2 | |
| CA2467276C | Canada | C | |
| CA2467295C | Canada | C | |
| CN1638304A | China | A | |
| FI20050748A | Finland | A | |
| FI20050748L | Finland | L | |
| CN1211948C | China | C | |
| MXPA99003034A | Mexico | A | |
| DE69533405T2 | Germany | T2 | |
| FI116342B | Finland | B | |
| EP1503517B1 | European Patent Office (EPO) | B1 | |
| FI20060862A | Finland | A | |
| FI20060862L | Finland | L | |
| AT339811T | Austria | T | |
| ATE339811T1 | Austria | T1 | |
| DE69535225D1 | Germany | D1 | |
| FI117840B | Finland | B | |
| ES2268553T3 | Spain | T3 | |
| RU2305363C2 | Russian Federation | C2 | |
| DE69535225T2 | Germany | T2 | |
| JP2007274730A | Japan | A | |
| CN101072058A | China | A | |
| JP2007318767A | Japan | A | |
| FI118662B | Finland | B | |
| EP1513268B1 | European Patent Office (EPO) | B1 |
Numbers
- Application
- 9704445
Titles2
- English
- METHOD AND APPARATUS FOR INCREASING RECEIVER IMMUNITY TO INTERFERENCE.
- Spanish
- METODO Y APARATO PARA INCREMENTAR LA INMUNIDAD A LA INTERFERENCIA DE UN RECEPTOR.
Classification
- CPC, 15
- H04W52/52
- H04B1/10
- H04B7/005
- H03F3/72
- H03F2203/7239
- H03G1/0088
- H03G3/3052
- H03G3/3068
- H04B1/109
- H04B1/70755
- H04B1/7097
- H03G3/30
- H03G1/00
- H04B1/06
- H04B1/16
- IPC, 14
- H03G1 00
- H04B1 06
- H03G3 30
- H04B
- H04B1 10
- H04B1 16
- H04B1 18
- H04B1 40
- H04B1 7075
- H04B1 7097
- H04B3 06
- H04B7 005
- H04B7 26
- H04B15 00