Receiver for receiving radio frequency signals

The present invention relates to a receiver for receiving radio frequency signals, and further relates to a tuner, a demodulator, a processing device, a method, and a processing program product.

Such a receiver corresponds to, for example, a television receiver having two or more receiving stages. The first radio frequency stage, for example, forms part of the tuner and / or corresponds to the tuner, and the second radio frequency stage, for example, forms the part of the demodulator and / or corresponds to the demodulator.

A receiver according to the prior art is known from EP0961492A2 (see Patent Document 1). It discloses a tuner that receives analog and digital television signals. A combination of two demodulators-detectors is provided so that both types of signals can be tuned and demodulated. Thereby, one of the above combinations is switched according to the type of signal being received and coupled to the tuner. To obtain automatic gain control (AGC), the detector is fed back to the tuner amplifier via a voltage conversion circuit.

Well-known receivers are disadvantageous, especially because they require AGC adjustment of the tuner during the manufacturing process. Since this adjustment is done manually, it makes the manufacturing process more costly, more time consuming, and more unreliable.<patcit num="1"><text>European patent application EP0961492A2</text></patcit><patcit num="2"><text>US patent application US 5,194,822</text></patcit>

<p> An object of the present invention is, in particular, to provide a receiver that does not require manual adjustment during the manufacturing process.</p><p> Furthermore, an object of the present invention is, in particular, to receive radio frequency signals without the need for manual adjustment with tuners, demodulators and processing devices used in receivers that do not require manual adjustment during the manufacturing process. To provide the method and computer program products.</p>

<p> The present invention is defined by the independent claims. Dependent claims define advantageous embodiments.</p><p> By providing a receiver with two or more gain controllers that control the gains of two or more stages independently of each other, manual adjustment is no longer necessary. As a result, the manufacturing process is cheaper, less time consuming, and more reliable. In addition, calibration, replacement and repair costs are avoided and an improved signal-to-noise ratio is achieved not only during the manufacturing process, but throughout the product life of the receiver, regardless of circuit control deviations.</p><p> It should be noted that it is known to use two gain controllers to control the gains of the two stages. However, these two gain controllers do not control the gain independently of each other, and the second gain controller also controls the first gain controller in the prior art. In these prior art environments, manual adjustments during the manufacturing process are still required.</p><p> A first embodiment of a receiver according to the invention is defined by claim 2. By adjusting both gain controllers to the same reference level and controlling the gain for this reference level, both stages are controlled for the same reference level. As a result, both stages are preferably coupled. (In addition, a better signal-to-noise ratio can be achieved.) This reference level is selected depending on the design during the design process.</p><p> A second embodiment of the receiver according to the invention is defined by claim 3. A first gain detector that detects the output signal of one or more of the first intermediate frequency amplifiers in the second stage, and a control input of the radio frequency amplifier in the first stage in response to the detection. A simple first gain controller is made by providing a first gain controller with a first gain generator that generates a first gain control signal to be supplied to the unit. It controls the gain of the first stage with a filter (eg, a SAW filter) placed between the first and second stages.</p><p> A third embodiment of the receiver according to the invention is defined by claim 4. To the second gain detector that detects the output signal of one or more intermediate frequency demodulation stages, and to the control input of one or more intermediate frequency amplifiers in the second stage according to the detection. A simple second gain controller is made by providing a second gain controller with a second gain generator that produces a second gain control signal to be supplied.</p><p> Each of the gain controllers is as disclosed in US 5,194,822 (Patent Document 2), for example, an analog / digital converter and a processing device having one or more memories such as a table memory. It may have a digital / analog converter. Alternatively, each gain controller may have a type of phase-locked loop or feedback loop structure.</p><p> Examples of the tuner according to the present invention, the demodulator according to the present invention, the processing apparatus according to the present invention, the method according to the present invention, and the processing program product according to the present invention correspond to the examples of the receiver according to the present invention.</p>

<p> The present invention is particularly based on the insight that manual adjustment makes the manufacturing process more costly, more time consuming and less reliable, and in particular gains from two or more stages from each other. It is based on the basic idea that two or more independently controlled gain controllers can replace this adjustment process.</p><p> The present invention specifically solves the problem of providing a receiver that does not require manual adjustment during the manufacturing process, and in particular, the manufacturing process is cheaper, less time consuming, and more reliable. It is advantageous in that it becomes. In addition, calibration, replacement and repair costs are avoided and an improved signal-to-noise ratio is achieved not only during the manufacturing process, but throughout the product life of the receiver, regardless of circuit control deviations.</p>

These and other features of the present invention will be described and clarified in more detail with reference to Examples described below.

The receiver 1 according to the present invention is shown in FIG. The receiver 1 has a radio frequency input unit 2 coupled to an antenna for receiving radio frequency signals such as various modulated carriers, and an intermediate frequency output unit 6 coupled to the input unit of the SAW filter 4. It has a first (radio frequency) stage 3. The output unit of the SAW filter 4 is coupled to the input unit 7 of the second (intermediate frequency) stage 5 having the video output unit 12 for generating a video signal. The first stage 3 further has an input unit 8 coupled to the control output unit 9 of the second stage 5.

The first stage 3 shown in FIG. 2 has a filter 30. The input unit of the filter 30 is coupled to the input unit 2, and the output unit of the filter 30 is coupled to the input unit of the radio frequency amplifier 31. The output section of the radio frequency amplifier 31 is coupled to the input section of the filter 32. The output section of the filter 32 is coupled to the first input section of the mixer 33. The output section of the mixer 33 is coupled to the input section of the filter 34. The output of the filter 34 is coupled to the input of another amplifier 35. The output section of another amplifier 35 is coupled to the output section 6. The first stage 3 further comprises a phase lock loop 36 (with a crystal clock if possible). The output section of the phase lock loop 36 is coupled to the input section of the oscillator 37. The first output of the oscillator 37 is coupled to the second input of the synthesizer 33, and the second output of the oscillator 37 is coupled to the control inputs of the filters 30 and 32. The input unit of the first gain controller 38 having the first gain detector 41 and the first gain generator 40 is coupled to the control input unit 8. The control input unit 42 of the first gain controller 38 receives the reference level signal REF, and the output unit of the first gain controller 38 receives the radio frequency amplifier 31 to change the amplification constant of the radio frequency amplifier 31. It is coupled to the control input unit 39 of.

The second stage 5, shown in FIG. 3, has one or more first intermediate frequency amplifiers 50. The input unit of the first intermediate frequency amplifier 50 is coupled to the input unit 7, and the output unit is coupled to one or more input units of the second intermediate frequency amplifier 51 and the control output unit 9. ing. The output section of the second intermediate frequency amplifier 51 is coupled to the first input section of the intermediate frequency demodulation stage 52. The output section of the intermediate frequency demodulation stage 52 is coupled to the input section of the video amplifier 53 and the input section of the second gain controller 54 having the second gain detector 59 and the second gain generator 58. There is. The output unit of the video amplifier 53 is coupled to the video output unit 12. The output section of the second gain controller 54 is coupled to the control input section 57 of the second intermediate frequency amplifier 51 in order to change the amplification constant of the second intermediate frequency amplifier 51. The control input unit 60 of the second gain controller 54 receives the reference level signal REF. The second stage 5 further comprises a phase lock loop 55. The phase-locked loop 55 has its first input section coupled to the output section of the second intermediate frequency amplifier 51, its second input section coupled to the output section of the oscillator 56, and its output section of the oscillator 56. It is connected to the input section. The output section of the oscillator 56 is further coupled to the second input section of the intermediate frequency demodulation stage 52.

The receiver 1 according to the present invention functions as follows. It is assumed that the radio frequency signal is received at 100 dBμV from the antenna to the radio frequency input unit 2. If the first stage 3 has a gain of 50 dB, the loss of the SAW filter 4 is 20 dB, and the first gain controller 38 is not operating, it will be supplied to the first intermediate frequency amplifier 50. The intermediate frequency signal is 130 dBuV. If this first intermediate frequency amplifier 50 has a gain of 5 dB (the gain of the first intermediate frequency amplifier 50 is chosen low to be more accurate, the higher the gain, the greater the deviation can be). The intermediate frequency signal at the output of the first intermediate frequency amplifier 50 is 135 dBuV. The first gain controller 38 compares 135 dBuV with the reference level set by the (intermediate) reference level signal REF, for example 100 dBuV. The difference between 135dBuV and 100dBuV produces the first gain control signal supplied to the control input 39 of the radio frequency amplifier 31 in the first stage 3. In response to this first gain control signal, the amplification constant of the radio frequency amplifier 31 is changed so that the first stage 3 obtains a gain of 20 dB (a decrease of 30 dB). In that case, the intermediate frequency signal supplied to the first intermediate frequency amplifier 50 is 105 dB. When the first intermediate frequency amplifier 50 has a gain of 5 dB, the intermediate frequency signal at the output section of the first intermediate frequency amplifier 50 is 100 dB. This is the reference level set by the (intermediate) reference level signal REF.

In the second stage 5, the second intermediate frequency amplifier 51 has, for example, two amplifiers with gains of 25 dB and 35 dB. The second gain controller 54 compares the output signal of the intermediate frequency demodulation stage 52 with a standard level, such as 2Vpp or 1Vpp. The difference between the output signal and this standard level gives rise to a second gain control signal supplied to the control input 57 of the second intermediate frequency amplifier 51 in the second stage 5. In response to this second gain control signal, the amplification constants of the second intermediate frequency amplifier 51 (one or both amplifiers) provide a gain such that the output signal of the intermediate frequency demodulation stage 52 is at standard level. Alternatively, the output signal of the second intermediate frequency amplifier 51 may be detected by the second gain controller 54. In general, the reference level set by the (intermediate) reference level signal REF determines the desired output level of the first intermediate frequency amplifier 50. The (intermediate) reference level signal REF supplied to the second gain controller 54 limits the gain reduction at the second intermediate frequency amplifier 51. The maximum gain reduction at the second intermediate frequency amplifier 51 is, for example, the (intermediate) reference level signal REF plus the gains of the first and second intermediate frequency amplifiers 50 and 51, and then the output signal of the intermediate frequency demodulation stage 52. Equal to the reference level set by subtracting the standard level of. However, this does not mean that other functions and / or equations are not allowed. The maximum gain reduction limit is needed to avoid excessive gain reduction at the second intermediate frequency amplifier 51, which worsens the signal-to-noise ratio.

By having the gain controllers 38 and 54 control the gains of the first and second stages 3 and 5 independently of each other, it is possible to advantageously avoid automatic gain control (AGC) adjustment during the manufacturing process. Become.

The second gain controller 54 includes, for example, an analog / digital converter, a processing device having one or more memories such as a table memory, and a digital / analog converter. In that case, the second gain detector 59 has an analog / digital converter and a part of the processing device and the memory, and the second gain generator 58 has the other part of the processing device and the memory. It has a digital / analog converter. In that case, the control input unit 60 forms, for example, the control input unit of the second gain detector 59 for receiving the reference level signal REF (eg, 100 dBuV or AGC DAC step 10). For example, the table below is implemented for that. (AGC DAC is an automatic gain control digital / analog converter.)

<tables num="1"><img file="JP2007516632A_D0001.tif" /></tables>The first gain controller 38 includes, for example, an analog / digital converter, a processing device having one or more memories such as a table memory, and a digital / analog converter. In that case, the first gain detector 41 has an analog / digital converter and a part of the processing device and the memory, and the first gain generator 40 has the other part of the processing device and the memory. It has a digital / analog converter. In that case, the control input unit 42 forms, for example, the control input unit of the first gain detector 41 for receiving the reference level signal REF (eg, 100 dBuV or AGC DAC step 10). By feeding the same reference level signal REF to the second gain controller 54 and the first gain controller 38, both stages 3 and 5 are gain controlled for the same reference level and are therefore optimally It is combined. This reference level is selected according to the design during the design process.

Alternatively, each of the gain controllers 38, 54 may have a kind of phase-locked loop or feedback loop structure. The first gain controller 38 may or may not form a portion of the first stage 3 and / or may or may not be incorporated in the radio frequency amplifier 31 and / or the first. It may or may not be incorporated in the intermediate frequency amplifier 50 of. The second gain controller 54 may or may not form a portion of the second stage 5 and / or may or may not be incorporated in the second intermediate frequency amplifier 51.

For example, "for" used in expressions such as "for A" and "for B" does not mean that other functions "C" are also executed at the same time. Absent. Expressions such as "X bound to Y" and "bonding between X and Y" and "bonding / joining X and Y" have elements Z between X and Y. It's not that I don't admit that. Expressions such as "P has Q" and "P with Q" do not mean that the element R is also included.

It should be noted that the examples described above do not limit the invention, but make it clear, and those skilled in the art will design a number of other examples without departing from the scope of the appended claims. Is what you can do. In the claims, the reference code placed in parentheses should not be construed to limit the claim. The use of the word "have" and its conjugation does not exclude the existence of elements or steps other than those stated in the claims. The article "one" in front of an element does not disallow the existence of more than one such element. The present invention may be implemented using hardware with several distinct elements and a properly programmed computer. In a device claim in which some means are listed, some of those means may be embodied by the same article of hardware. The fact that certain methods are listed in different dependent claims does not indicate that a combination of those methods cannot be used in an advantageous manner.

<figref num="1">A schematic diagram of a receiver according to the invention having a first stage and a second stage is shown.</figref><figref num="2">A schematic diagram of the first stage with the first gain controller is shown.</figref><figref num="3">A schematic of a second stage with a second gain controller is shown.</figref>