Demodulator

[Detailed Description of the Invention]

Field of the Invention The present invention reproduces the subcarrier of a digital subcarrier abnormal-conditions signal, and relates to the recovery device which performs synchronous detection and to which it restores. PRIOR ART In Boardous Digicle communication, many multi-Value orthogonal vibration 1 Sag modulation method with high frequency utilization efficiency are used in recent years. What depends such a modulation method on digital signal processing advantageous to LSI-izing etc. as a subcarrier reproduction means for carrying out synchronous detection is proposed. Below, while referring to drawings for the subcarrier playback equipment by the conventional digital signal processing to a 16QAM signal, it explains. Drawing 6 is a lineblock diagram of conventional subcarrier playback equipment. A 16QAM signal is inputted from input terminal 101. An input signal is changed into digital signal 105 with A/D conversion machine 104. On the other hand, after a phase is changed into an input signal only pi/2 in Transfer phase circuit 102, it is changed into digital signal 106 with A/D conversion machine 103. Therefore, signal 105 and signal 106 turn into a signal with which the phase intersected perpendicularly mutually. Phase detector circuit 107 can detect the phase of signal 105 irrespective of signal amplitude by doing division of signal 105 and the signal 106 mutually, and asking for the reverse right Contact. The detected topology serves as signal 115 with which phase contrast is expressed by subtraction circuit 10B. Here, it precedes describing phase conversion circuit 109, and a 16QAM signal is shown briefly. In the plane which consists of two axes in sync with a subcarrier which intersect perpendicularly mutually, Drawing 7 shows 16 signal points of a 16QAM signal. From Drawing 7, 16 signal points come four with one phase of ±theta1~±theta6. Therefore, when the input-and-output characteristic considers it as the characteristic shown in Drawing 8 as between [ B109 ] phase conversion of Drawing 6, the output proportional to the phase contrast from an original signal point is obtained. Now, it returns to Drawing 6 again, and after signal 116 which is an output from phase conversion circuit 109 passes through switch 110 with which method control of To only of the time when a signal point exists with timing signal 104 is shut and carried out, it is led to Rua filter 111 which defines the response characteristic of a loop while it oppresses an unnecessary ingredient. Voltage control oscillating circuit 112 sends on the frequency according to the output of loop filter 111, and outputs the phase signal 113. Phase signal 113 returns to subtraction circuit 108, and constitutes a phase simulation loop. a subcarrier of a 1 6QAM signal into which phase signal 113 acquired by above-mentioned composition and operation was inputted -- frequency -- and phase simulation is carried out. It is outputted from output terminal 117 as a reproduction subcarrier phase signal. The conventional subcarrier playback equipment described above is indicated, for example to the Institute of Electronics and Communication Engineers paper magazine, a J69-B volume, No. 12, P, 1676~P, and 1684 (December, 1986). Object of the Invention However, in the above-mentioned composition, in order the phase shift means which changes a phase only pi/2 correctly is needed in the phase of a signal and also to acquire a recovery signal, there is a problem that a circuit scale becomes large -- the recovery circuit which restores to an input signal based on the reproduced subcarrier is needed separately. There are the following things as further subject. That is, in the signal point of the 16QAM signal shown in Drawing 7, the phase angle of signal point I that amplitude is comparatively small is theta by noise etc. at phase angle theta 2. Or it changes easily near theta 8. As a result, in the above-mentioned conventional composition, the phase of signal point 1 will be wrong to theta1 or theta3, and will be drawn by the crowd power characteristic of phase conversion circuit 109 shown in Drawing 8, and the subject that the right subcarrier phase may not be reproduced occurs. Such malfunction will become much more serious, if the number of many values of a multi-value quadrature amplitude modulation increases. Then, it is necessary to establish separately neither a phase shift means nor a demodulation means, therefore can realize by a small circuit scale, and the present invention sets it as the first purpose to provide the recovery device which performs subcarrier reproduction and a recovery. It sets it as the second purpose to provide the recovery device which performs subcarrier reproduction correctly, without being drawn in the phase mistaken by noise etc. Means for solving problem The demodulation means in which the recovery device of the present invention obtains two orthogonal demodulated signals which intersect perpendicularly mutually from an input signal and two reproduction subcarriers which intersect perpendicularly mutually in order to solve the above-mentioned subject, The phase detecting means which detects the phase of a recovery signal from two orthogonal demodulated signals, It has a generating To shake variable frequency oscillation means for two reproduction subcarriers which oscillate and intersect perpendicularly on the frequency according to the output of the phase signal conversion means which outputs a predetermined value according to a phase, the filter means which considers the output of a phase signal conversion means as an input, and a filter means. The amplitude detection means which detects the amplitude of a recovery signal from two orthogonal demodulated signals is newly added to the above-mentioned composition, and a phase signal conversion means is constituted so that a predetermined value may be outputted according to a phase and amplitude. OPERATION It is necessary to establish separately neither a phase shift means nor a demodulation means, therefore can perform reproduction of a subcarrier, and the recovery by synchronous detection simultaneously in a small circuit scale by the above-mentioned composition. Since the characteristic of a phase conversion method is optimized according to signal point arrangement according to the amplitude of an input signal, it is strong to phase change of the signal point by noise etc., and reproduction and a recovery of the right subcarrier can be performed, without drawing in the wrong phase. EXAMPLE Below, while referring to drawings for the first example of the present invention, it explains. Drawing 1 is a lineblock diagram showing the first example of the recovery device of the present invention. In The 1:J, bitter taste, and a signal equivalent to the conventional subcarrier playback equipment previously shown in Drawing 1 in Drawing 6, it is A] Si It was about the number. An IGQAM signal is inputted from input terminal 101. An input signal is changed into a digital signal with A/D conversion machine 201. Reproduced subcarrier signals 212 and 213 which mention the digitized signal below in multiplication circuits 202 and 203 and which intersect perpendicularly mutually are multiplied, respectively. In low pass filter (■, PF) 204 and low pass filter (I, PF) 205, as for the multiplied signal, an unnecessary ingredient is removed, respectively. The signal acquired in this way turns into recovery signals 206 and 207 which intersect perpendicularly mutually, and is outputted from recovery signal output terminals 210 and 211, respectively. Signals 206 and 207 are simultaneously inputted into phase detector circuit 107. Phase detector circuit 107 detects the phase of signal 206 like the case of a previous conventional example. Hereinafter, reproduction subcarrier phase signal 113 is acquired like a conventional example through switch 110, loop filter 111, and voltage control oscillating circuit 112. By cosine wave conversion circuit 209 which changes topology into sine wave conversion circuit 20B and the cosine wave which are changed into a sine wave, reproduction subcarrier phase signal 113 turns into reproduction subcarrier signals 212 and 213 which intersect perpendicularly mutually, and returns to the above-mentioned multiplication circuit, respectively. as a result -- constituting a phase simulation loop -- reproduction subcarrier phase signal 113 -- a conventional example -- the same -- the subcarrier of an input 16QAM signal -- frequency -- and phase simulation is carried out. As mentioned above, according to this example, while reproducing a subcarrier, the recovery by synchronous detection can be performed, without establishing a new demodulation means, and it can realize by a comparatively small circuit scale. Below, the second example of the present invention is described. Drawing 2 is a lineblock diagram showing the second example of the recovery device of the present invention. Said was carried out to the first previous example, and the number was given to the block of a function, and the signal. Different points from the first example are that amplitude detection circuit 220 was provided and that phase conversion circuits 221 differ. amplitude detection circuit 220 detects the button width of a signal by asking for the square root of the square sum of recovery signals 206 and 207 which intersected perpendicularly mutually --] -- a dragon -- I Singing u ';; It outputs as 222. such an amplitude detection circuit 220 -- input-and-output relations -- oh, the read-only memory etc. which were caulked and memorized can constitute easily. Amplitude signal 222 is inputted into phase conversion circuit 221 with signal 115 showing a phase, and it is outputted to it in signal 116 of the value according to these two signals. Now, it explains in detail about phase conversion circuit 221. Drawing 3 shows the composition of phase conversion circuit 221 of this example. the input-and-output characteristic table where signals 115 differ mutually -- oh -- read-only memory (ROM is called below) 310 and 311 caulked and memorized -- input To be. The input-and-output characteristic by ROM310 is the characteristic which outputs O, when the phases which signal 115 shows are ±theta2 and ±theta5, as shown in Drawing 4. The input-and-output characteristic of a direction by ROM311 is the characteristic which outputs 0, when the phases which phase contrast signal 115 shows are ±theta1 *±theta8.±theta4 and ±theta6, as shown in Drawing 5. With reference to signal point arrangement of the 16QAM signal shown in Drawing 7 here, distance from the starting point of signal points 1, 5.9, and 13 is set to a, and it of signal point 2*4.6, 8.10, and 12.14 and 16 will be set to b, and also it of signal points 3-7.11 and 15 will be expressed as C. At this time, the signal amplitude which amplitude signal 222 shows distinction circuit 312 of Drawing 3, a b It controls so that switch 313 connects with the bottom, in being the closest to b among c, and it controls so that switch 313 connects with the upper part, when the signal amplitude which amplitude signal 222 shows is the closest to a or C. As a result, when signal point 1 of Drawing 7 is transmitted, for example, switch 313 of Drawing 3 is connection To 1 to the upper part. To be. Therefore, even if the phase angle of signal point 1 changed with noises etc. near theta1 or theta3, the input-and-output characteristic of the phase conversion circuit shown in Drawing 4 is wrong, and it is not drawn in phases, such as theta 1 or theta 3. It is clear that the result which may be similarly compared with a previous conventional example about other signal points is obtained. Since the phase conversion circuit is optimizing the crowd power characteristic of a phase conversion circuit according to signal point arrangement according to amplitude not only with reference to a phase signal but with reference to amplitude according to this example as explained above, the phase which was strong to phase change of the signal point by noise etc., and wrong -- Yukikomu -- the right subcarrier phase [ be / nothings ] can be reproduced, therefore the right recovery can be performed. Although the above-mentioned example targeted the 16QAM signal, it is clear by changing the characteristic of a phase conversion circuit in the case of other multi-value quadrature amplitude modulations that it can respond easily. 2 by which the present invention is limited to this although all were considered as the composition by Digicle processing in the above-mentioned example There are nothings and it may carry all out from analog processing Turn in part. EFFECT OF THE INVENTION Since it is necessary to establish separately neither a phase shift means nor a demodulation means like a conventional example, it can realize by a small circuit scale, and the recovery device of the present invention can perform subcarrier reproduction and a recovery simultaneously so that clearly from the above explanation. By optimizing the characteristic of a phase conversion method according to signal point arrangement according to signal amplitude, it is strong to phase change of the signal point by noise etc., and without drawing in the wrong phase, the right subcarrier can be reproduced and it can get over.

[Brief Description of the Drawings]

Drawings 2 are a lineblock diagram in which Drawing 1 shows the first example of the recovery device of the present invention, and a lineblock diagram showing the second example of the recovery device of the present invention, In the lineblock diagram and Drawings 4 and 5 of the phase conversion circuit in the second example of the present invention, Drawing 3 is input-and-output characteristic figures by ROM310311 in Drawing 3, respectively, the lineblock diagram showing the subcarrier playback equipment of the former [ Drawing / 6 ], and Drawing 7 -- f No. 3 point of a 16QAM signal -- an account Place figure and Drawing 8 are input-and-output characteristic figures of the phase conversion circuit in the conventional subcarrier re-" Yu device. 107 ...... A phase detector circuit, 109 ...... A phase conversion circuit, 111 ...... [ ...... A multiplier, '204.205 / ...... A low pass filter, 208 / ...... A sine wave conversion circuit, 209 / ...... Cosine wave conversion circuit. ] A loop filter, 112 ...... A voltage control oscillating circuit, 201 ...... An A/D conversion machine, 202.203