JPH0125259B2 - - Google Patents
Info
- Publication number
- JPH0125259B2 JPH0125259B2 JP54025869A JP2586979A JPH0125259B2 JP H0125259 B2 JPH0125259 B2 JP H0125259B2 JP 54025869 A JP54025869 A JP 54025869A JP 2586979 A JP2586979 A JP 2586979A JP H0125259 B2 JPH0125259 B2 JP H0125259B2
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- JP
- Japan
- Prior art keywords
- phase
- signal
- output
- amplitude
- detector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000010354 integration Effects 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 description 14
- 238000010586 diagram Methods 0.000 description 13
- 238000004891 communication Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C1/00—Amplitude modulation
- H03C1/02—Details
- H03C1/04—Means in or combined with modulating stage for reducing angle modulation
Landscapes
- Amplifiers (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Description
【発明の詳細な説明】
本発明は振幅−位相変換特性を有する非線形通
信路により歪を受けた信号を受信側で等化する復
調回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a demodulation circuit that equalizes a signal distorted by a nonlinear channel having amplitude-phase conversion characteristics on a receiving side.
衛星通信、地上マイクロ波通信等における電力
増幅器は一般に非線形入出力特性を有する。この
非線形特性には出力信号の振幅が入力信号の振幅
に比例しないという振幅−振幅変換（以後−AM
−AM変換と略す）の他に、入力信号の振幅によ
つて出力信号の位相回転量が変るという振幅−位
相変換（以後AM−PM変換と略す）がある。こ
のような非線形増幅器を有する通信路を通して多
値多相デイジタル信号を伝送する場合、信号の大
きさ、すなわち、伝送する信号点により位相回転
量が変り、伝送特性が劣化するという現象が生ず
る。 Power amplifiers used in satellite communications, terrestrial microwave communications, etc. generally have nonlinear input/output characteristics. This nonlinear characteristic includes amplitude-to-amplitude conversion (hereinafter referred to as −AM
-AM conversion), there is also amplitude-phase conversion (hereinafter abbreviated as AM-PM conversion) in which the amount of phase rotation of an output signal changes depending on the amplitude of an input signal. When transmitting a multi-level, multi-phase digital signal through a communication path having such a nonlinear amplifier, a phenomenon occurs in which the amount of phase rotation changes depending on the magnitude of the signal, that is, the signal point to be transmitted, and the transmission characteristics deteriorate.
このような通信路を介して信号を伝送する場
合、非線形歪除去のために従来は増幅器を線形な
領域で使用するという方法を採用している。第１
図はTWTA（Travelling Wave Tube）等の非線
形増幅器のAM−AM変換特性およびAM−PM
変換特性の一例を示す図である。横軸は入力信号
振幅を示し、縦軸は出力信号振幅および位相回転
量を示す。出力振幅は入力振幅のあるa2まで比例
し、それ以後は比例せずにAM−AM変換歪を生
ずる。 When transmitting signals through such a communication channel, a conventional method has been adopted in which an amplifier is used in a linear region in order to remove nonlinear distortion. 1st
The figure shows AM-AM conversion characteristics and AM-PM of nonlinear amplifiers such as TWTA (Travelling Wave Tube).
FIG. 3 is a diagram showing an example of conversion characteristics. The horizontal axis shows the input signal amplitude, and the vertical axis shows the output signal amplitude and phase rotation amount. The output amplitude is proportional to the input amplitude up to a certain point a2 , and thereafter it is not proportional and AM-AM conversion distortion occurs.
一方、位相回転量はa2よりも小さな入力振幅a1
で大きく増加しはじめる。このため、増幅器を線
形領域で動作させるためには入力振幅をa1よりも
小さくしなければならず、振幅特性の線形領域の
最大出力であるb2よりもはるかに小さな出力b1
（入力a1に対応する）までしか利用できないとい
う欠点がある。 On the other hand, the amount of phase rotation is smaller than input amplitude a 1 than a 2
begins to increase significantly. Therefore, in order for the amplifier to operate in the linear region, the input amplitude must be smaller than a 1 , and the output b 1 is much smaller than b 2 , which is the maximum output in the linear region of the amplitude characteristic.
The drawback is that it can only be used up to (corresponding to input a 1 ).
本発明の目的は従来の非線形歪を除く手段にお
ける上述の欠点を除き増幅器をより大きな出力で
動作させることを可能にする復調回路を提供する
ことにある。 SUMMARY OF THE INVENTION An object of the present invention is to provide a demodulation circuit which eliminates the above-mentioned drawbacks of conventional means for removing nonlinear distortion and allows an amplifier to operate at a higher output.
次に図面を参照して本発明の構成および動作原
理を詳細に説明する。 Next, the configuration and operating principle of the present invention will be explained in detail with reference to the drawings.
第２図は本発明の第１の実施例を示すブロツク
図である。被復調信号用入力端子２０１には多値
多相デイジタル信号が印加されるが、以後の説明
においては、印加信号を第３図に示す16QAM
（Quadrature Amplitude Modulation−直交振
幅変調）のアナログサンプル信号と仮定する。た
だし、このことは本発明の適用範囲を限定するも
のではない。 FIG. 2 is a block diagram showing a first embodiment of the present invention. A multilevel multiphase digital signal is applied to the demodulated signal input terminal 201, but in the following explanation, the applied signal will be 16QAM as shown in FIG.
(Quadrature Amplitude Modulation) is assumed to be an analog sample signal. However, this does not limit the scope of application of the present invention.
第３図において、Ｉ，Ｑは二つの直交した軸を
表わし、P1，P2，P3，P4は第１象現における最
適なデータ点を表わす。また、A1，A2，A3，A4
は各データ点の原点からの距離、振幅を表わす。
この16QAM信号がAM−PM変換特性をもつ増
幅器により増幅されると、振幅A1，A2，A3およ
びA4に応じてそれぞれ位相回転θ1，θ2，θ3および
θ4を受ける。この結果、各点はP1′，P2′，P3′およ
びP4′の位置に動く。これらの信号P1′，P2′，P3′，
P4′は本発明における入力端子２０１に印加され
る。 In FIG. 3, I and Q represent two orthogonal axes, and P 1 , P 2 , P 3 and P 4 represent the optimal data points in the first quadrant. Also, A 1 , A 2 , A 3 , A 4
represents the distance and amplitude of each data point from the origin.
When this 16QAM signal is amplified by an amplifier having AM-PM conversion characteristics, it undergoes phase rotations θ 1 , θ 2 , θ 3 and θ 4 according to amplitudes A 1 , A 2 , A 3 and A 4 , respectively. As a result, the points move to positions P 1 ′, P 2 ′, P 3 ′, and P 4 ′. These signals P 1 ′, P 2 ′, P 3 ′,
P 4 ' is applied to input terminal 201 in the present invention.
端子２０１の出力は位相制御器２０２に印加さ
れ、その出力信号は参照搬送波発生器２０３の出
力信号との間に位相差をもつている。この二つの
信号は乗積検波器２０４に印加され、その出力信
号（振幅と参照搬送波との位相差情報を含む
P1′〜P4′を示す信号）は識別器２０５に印加され
る。識別器２０５はP1′〜P4′（第３図）を入力信
号として閾値T1，T2によりP1〜P4を含む領域
（第３図の１マスの領域）のいずれにあるかを判
定し、復調回路出力端子２０６に判定結果を出力
する。もし入力信号が第３図のデータ点P1を含
む領域にあるならば出力はA1ej〓1（φ1はP1の位相
量）、データ点P2を含む領域にあるならば出力は
A2ej〓2（φ2はP2の位相量）、データ点P3を含む領域
にあるならば出力はA3ej〓3（φ3はP3の位相量）、デ
ータ点P4を含む領域にあるならば出力はA4ej〓4
（φ4はP4の位相量）である。 The output of terminal 201 is applied to phase controller 202, and its output signal has a phase difference with the output signal of reference carrier generator 203. These two signals are applied to the product detector 204, and its output signal (including amplitude and phase difference information with the reference carrier
P 1 ' to P 4 ') are applied to the discriminator 205. The discriminator 205 uses P 1 ′ to P 4 ′ (Fig. 3) as input signals and uses thresholds T 1 and T 2 to determine which of the regions including P 1 to P 4 (region of one square in Fig. 3) is located. is determined, and the determination result is output to the demodulation circuit output terminal 206. If the input signal is in the region including data point P 1 in Figure 3, the output is A 1 e j 〓 1 (φ 1 is the phase amount of P 1 ), and if it is in the region including data point P 2 , the output is teeth
A 2 e j 〓 2 (φ 2 is the phase amount of P 2 ), if it is in the area that includes data point P 3 , the output is A 3 e j 〓 3 (φ 3 is the phase amount of P 3 ), data point P If it is in the region containing 4 , the output is A 4 e j 〓 4
(φ 4 is the phase amount of P 4 ).
位相回転量検出器２０７は識別器２０５の出力
およびP1′〜P4′の信号をもとにP1′〜P4′の位相回
転量θ1〜θ4を検出しその位相回転量に応じた電圧
を発生する。ここでP1′〜P4′の信号とは乗積検波
器２０４の出力信号で、それぞれa1ej〓1，a2ej〓2，
a3ej〓3，a4ej〓4と表せる。ただし、a1，a2，a3，a4
はそれぞれP1′，P2′，P3′，P4′の振幅、1，2，
3，4はそれぞれの位相を表わす。したがつて、
次の関係から位相回転量θ1〜θ4を求める。 The phase rotation amount detector 207 detects the phase rotation amounts θ 1 to θ 4 of P 1 ′ to P 4 ′ based on the output of the discriminator 205 and the signals of P 1 ′ to P 4 ′ , and uses the phase rotation amounts as Generates the appropriate voltage. Here, the signals P 1 ′ to P 4 ′ are the output signals of the product detector 204, and are respectively a 1 e j 〓 1 , a 2 e j 〓 2 ,
It can be expressed as a 3 e j 〓 3 , a 4 e j 〓 4 . However, a 1 , a 2 , a 3 , a 4
are the amplitudes of P 1 ′, P 2 ′, P 3 ′, P 4 ′, 1 , 2 ,
3 and 4 represent the respective phases. Therefore,
The phase rotation amounts θ 1 to θ 4 are determined from the following relationships.
θ1＝1−φ1 θ2＝2−φ2
θ3＝3−φ3 θ4＝4−φ4
一方、包絡線検波器２０９は被復調信号の振幅
a1〜a4を検出し、関数発生器２０８に与える。こ
の関数発生器２０８は振幅a1〜a4と位相回転量検
出器２０７の出力信号を取り込み、振幅a1〜a4に
応じて位相制御器２０２に制御信号を出力し、入
力信号の位相を各振幅ごとに徐々に制御する。す
なわち、関数発生器２０８の出力信号は位相制御
器２０２を駆動してAM−PM変換による位相回
転量θ1〜θ4を減らす方向に端子２０１からの入力
信号の位相を制御する。これによつて位相回転量
検出器２０７では位相回転量θ1〜θ4の検出量が
徐々に小さくなり、最終的にθ1〜θ4の検出量が０
になると関数発生器２０８の出力信号すなわち位
相制御器２０２への制御信号が固定され、位相制
御器２０２による位相制御動作が終了する。 θ 1 = 1 −φ 1 θ 2 = 2 −φ 2 θ 3 = 3 −φ 3 θ 4 = 4 −φ 4 Meanwhile, the envelope detector 209 detects the amplitude of the demodulated signal.
A 1 to a 4 are detected and provided to the function generator 208 . This function generator 208 takes in the amplitudes a 1 to a 4 and the output signal of the phase rotation amount detector 207, outputs a control signal to the phase controller 202 according to the amplitudes a 1 to a 4 , and changes the phase of the input signal. Gradually control each amplitude. That is, the output signal of the function generator 208 drives the phase controller 202 to control the phase of the input signal from the terminal 201 in a direction that reduces the phase rotation amounts θ 1 to θ 4 due to AM-PM conversion. As a result, in the phase rotation amount detector 207, the detected amounts of the phase rotation amounts θ 1 to θ 4 gradually become smaller, and finally the detected amounts of θ 1 to θ 4 become 0.
When this occurs, the output signal of the function generator 208, that is, the control signal to the phase controller 202, is fixed, and the phase control operation by the phase controller 202 is completed.
位相制御動作が終了したときに位相制御器が調
整する位相量は、第８図に示すように第１図に示
す特性を横軸を対称して負側に反転させた特性と
ほぼ等価となり、電力増幅器のAM−PM変換特
性（第１図）を補償する関数となる。この関数は
関数発生器２０８の出力信号の振幅を縦軸にとつ
たものと相似となる。 The phase amount adjusted by the phase controller when the phase control operation is completed, as shown in FIG. 8, is approximately equivalent to the characteristic shown in FIG. 1 reversed to the negative side symmetrically with respect to the horizontal axis, This is a function that compensates for the AM-PM conversion characteristics (Fig. 1) of the power amplifier. This function is similar to the one whose vertical axis is the amplitude of the output signal of the function generator 208.
本発明に用いられる乗積検波器２０４は直交検
波を行うもので、例えば、第５図に示す構成を有
している。端子５０１の入力信号は二つに分割さ
れ、一方は端子５０２に印加された一定の振幅と
周波数を有する参照搬送波と掛算器５０３により
積をとられ、その積はフイルタ５０４を介して一
つの直交軸の検波出力として端子５０５に出力さ
れる。端子５０１の入力信号の他方は、移相器５
０６により90゜の位相差をもたされた参照搬送波
とともに掛算器５０７に印加され積をとられた
後、フイルタ５０８を介して他の直交軸の検波出
力として端子５０９に出力される。端子５０１お
よび５０２はそれぞれ乗積検波器２０４の二つの
入力端子に相当し、二つの出力端子５０５および
５０９は乗積検波器２０４の出力端子に相当す
る。 The product detector 204 used in the present invention performs orthogonal detection and has, for example, the configuration shown in FIG. 5. An input signal at a terminal 501 is divided into two parts, one of which is multiplied by a reference carrier wave having a constant amplitude and frequency applied to a terminal 502 by a multiplier 503, and the product is divided into two by a multiplier 503, and the product is divided into two parts by a multiplier 503. It is output to a terminal 505 as a detected output of the axis. The other input signal of the terminal 501 is connected to the phase shifter 5.
After being applied to a multiplier 507 together with a reference carrier wave having a phase difference of 90 degrees by 06 and the product thereof being multiplied, the signal is outputted to a terminal 509 via a filter 508 as a detection output of another orthogonal axis. Terminals 501 and 502 correspond to two input terminals of product detector 204, respectively, and two output terminals 505 and 509 correspond to output terminals of product detector 204.
位相回転量検出器２０７は、例えば、第６図に
示す構成を有する。第６図において、端子６０
１，６０２は検出器２０７の二つの入力端子で、
端子６０１には乗積検波器２０４の出力、端子６
０２には識別器２０５の出力が印加される。端子
６０３は検出器２０７の出力端子に相当する。端
子６０１および６０２の信号は前述した複素信号
であり、移相器６０４により90゜の位相差をもた
され、掛算器６０５により積をとられる。掛算器
６０５は複素掛算を行い、その実数部を出力す
る。たとえば、入力データがP1′である場合を考
えると、端子６０１に印加される信号はa1ej〓1、
端子６０２に印加される信号はA1ej 1となり、移
相器６０４の出力はA1e(j 1+〓/2）となる。掛算器
６０５の出力は実数部なので、
Re｛a1ej 1×A1ej(〓1+〓/2)｝
＝A1a1cos（1−φ1−π／２）
A1a1sin（1−φ1）
＝A1a1sinθ1
となる。入力データがP2′，P3′，P4′である場合
も同様に位相回転量θ2，θ3，θ4が検出される。 The phase rotation amount detector 207 has a configuration shown in FIG. 6, for example. In FIG. 6, terminal 60
1,602 are two input terminals of the detector 207,
The terminal 601 has the output of the product detector 204, and the terminal 6
The output of the discriminator 205 is applied to 02. Terminal 603 corresponds to the output terminal of detector 207. The signals at terminals 601 and 602 are the above-mentioned complex signals, are given a phase difference of 90° by phase shifter 604, and are multiplied by multiplier 605. Multiplier 605 performs complex multiplication and outputs the real part. For example, if the input data is P 1 ', the signal applied to the terminal 601 is a 1 e j 〓 1 ,
The signal applied to the terminal 602 becomes A 1 e j 1 , and the output of the phase shifter 604 becomes A 1 e (j 1+ 〓 /2 ). Since the output of the multiplier 605 is the real part, Re{a 1 e j 1 ×A 1 e j( 〓 1+ 〓 /2) } =A 1 a 1 cos( 1 −φ 1 −π/2) A 1 a 1 sin ( 1 − φ 1 ) = A 1 a 1 sin θ 1 . Phase rotation amounts θ 2 , θ 3 , and θ 4 are similarly detected when the input data is P 2 ′, P 3 ′ , and P 4 ′ .
第７図は本発明に用いられる位相回転量検出器
２０７および関数発生器２０８の具体的な構成例
を示した図である。端子７０１，７０２は位相回
転量検出器２０７の二つの入力端子を表わし第６
図の端子６０１，６０２に相当する。端子７０３
は関数発生器の包絡線検波器２０９からの入力端
子を表わし、端子７０４は関数発生器の出力端子
を表わす。本構成例においては、端子７０１，７
０２の信号は複素信号であり、移相器７０５によ
り90゜の位相差を与えられたあと、掛算器７０６
に印加される。掛算器７０６は複素掛算を行いそ
の実数部を位相差信号として出力する。切替スイ
ツチ７０７は端子７０２の信号により制御され、
該信号の振幅に応じてその接続すべき接点が選ば
れる。接点の数は端子７０２の信号のとり得る振
幅数により決るものである。その振幅数は第３図
の16QAM信号の場合、A1，A2（＝A4），A3の３
つである。切替スイツチ７０７は各振幅に応じて
位相差信号A1a1sinθ1，A2a2sinθ2（A4a4sinθ4），
A3a3sinθ3を選択しそれぞれ別の出力端子に出力
する。 FIG. 7 is a diagram showing a specific configuration example of the phase rotation amount detector 207 and the function generator 208 used in the present invention. Terminals 701 and 702 represent two input terminals of the phase rotation amount detector 207.
This corresponds to the terminals 601 and 602 in the figure. Terminal 703
represents the input terminal from envelope detector 209 of the function generator, and terminal 704 represents the output terminal of the function generator. In this configuration example, terminals 701, 7
The signal 02 is a complex signal, and after being given a phase difference of 90° by a phase shifter 705, it is sent to a multiplier 706.
is applied to Multiplier 706 performs complex multiplication and outputs the real part as a phase difference signal. The changeover switch 707 is controlled by the signal at the terminal 702,
The contact to be connected is selected depending on the amplitude of the signal. The number of contacts is determined by the number of possible amplitudes of the signal at the terminal 702. In the case of the 16QAM signal shown in Figure 3, the number of amplitudes is 3 of A 1 , A 2 (=A 4 ), and A 3
It is one. The changeover switch 707 selects phase difference signals A 1 a 1 sin θ 1 , A 2 a 2 sin θ 2 (A 4 a 4 sin θ 4 ),
Select A 3 a 3 sinθ 3 and output each to separate output terminals.
切替スイツチ７０７の各接点は関数発生器２０
８の積分器I1〜Ioに接続され、各積分器は振幅に
応じた位相差信号を蓄積し、各々の出力端子に出
力する。積分器I1〜Ioの出力端子は関数発生器２
０８の選択回路７０８の入力端子に接続されてい
る。選択回路７０８は端子７０３に印加された入
力信号の振幅を表わす信号に応じて所定の積分器
の出力を取り込む。たとえば振幅がa1のときは位
相差信号A1a1sinθ1を積分する積分器の出力、振
幅がa2のときA2a2sinθ1（A4a4sinθ4）を積分する
積分器の出力、振幅がa3のときA3a3sinθ3を積分
する積分器の出力を選択する。選択回路７０８の
出力信号によつて位相制御器２０８はAM−PM
変換による位相回転量θ1〜θ4を０にするよう入力
信号の位相を徐々に制御する。位相回転量θ1〜θ4
がそれぞれ最終的に０になるとすなわち掛算器７
０６の出力が０になると、関数発生器２０８の出
力は固定され位相補正が終了する。このときの位
相制御量は前述したように第８図に示すとおりで
あり、また関数発生器２０８の出力特性も第８図
の縦軸を出力振幅としたものと相似となる。これ
は関数発生器の出力振幅と位相制御量は１対１に
対応しているからである。 Each contact of the changeover switch 707 is connected to the function generator 20.
It is connected to eight integrators I1 to Io , and each integrator accumulates a phase difference signal according to the amplitude and outputs it to its respective output terminal. The output terminals of integrators I 1 to I o are function generator 2
It is connected to the input terminal of the selection circuit 708 of 08. Selection circuit 708 takes in the output of a predetermined integrator in response to a signal representing the amplitude of the input signal applied to terminal 703. For example, when the amplitude is a 1 , the output of an integrator that integrates the phase difference signal A 1 a 1 sin θ 1 , and when the amplitude is a 2 , the output of an integrator that integrates the phase difference signal A 1 a 1 sin θ 1 (A 4 a 4 sin θ 4 ) Select the output of the integrator that integrates A 3 a 3 sinθ 3 when the output and amplitude are a 3 . The output signal of the selection circuit 708 causes the phase controller 208 to switch between AM and PM.
The phase of the input signal is gradually controlled so that the amount of phase rotation θ 1 to θ 4 due to conversion becomes zero. Phase rotation amount θ 1 ~ θ 4
When each finally becomes 0, that is, the multiplier 7
When the output of function generator 208 becomes 0, the output of function generator 208 is fixed and phase correction is completed. The phase control amount at this time is as shown in FIG. 8, as described above, and the output characteristic of the function generator 208 is also similar to that in FIG. 8, where the vertical axis is the output amplitude. This is because the output amplitude of the function generator and the phase control amount have a one-to-one correspondence.
第４図は本発明の第２の実施例を示す図であ
る。本実施例においては、位相変調器２０２を参
照搬送波発生器２０３の出力端子と乗積検波器２
０４の入力端子との間に挿入し、端子２０１の信
号に変調をかける代りに搬送波に変調をかけるも
ので、その効果は第１の実施例と同じである。 FIG. 4 is a diagram showing a second embodiment of the present invention. In this embodiment, the phase modulator 202 is connected to the output terminal of the reference carrier generator 203 and the product detector 2
04 and modulates the carrier wave instead of modulating the signal at terminal 201, and the effect is the same as in the first embodiment.
以上のように、本発明の復調回路は、非線形増
幅器によるAM−PM変換を等化して正しい復調
を行うことを可能にするもので、多値・多相デイ
ジタル変調信号の受信器に適用すれば極めて有効
である。 As described above, the demodulation circuit of the present invention makes it possible to perform correct demodulation by equalizing AM-PM conversion by a nonlinear amplifier. Extremely effective.
第１図は非線形増幅器の入出力特性の例を示す
図、第２図は本発明による第１の実施例を示す
図、第３図は16QAM信号のデータ点およびAM
−PM変換を受けたデータ点を示す図、第４図は
本発明による第２の実施例を示す図、第５図は第
２図における乗積検波器の例を示す図、第６図は
第２図における制御器の構成例を示す図、第７図
は第２図の制御器および関数発生器の他の構成例
を示す図、第８図は第１図に使用する位相制御器
における最終的な入力信号振幅対位相特性を示す
線図である。
図中、２０１は信号入力端子を、２０２は位相
制御器、２０３は参照搬送波発生器、２０５は識
別器、２０６は復調信号出力端子、２０７は位相
回転量検出器、２０８は関数発生器、２０９は包
絡線検波器、５０１，５０２は直交乗積検波器、
２０４の二つの入力端子、５０３，５０７は乗積
検波器、５０４，５０８はフイルタ、６０１，６
０２は位相回転量検出器２０７の二つの入力端
子、６０３は位相回転量検出器２０７の出力端
子、６０４は90゜移相器、６０５は掛算器、６０
６は積分器、７０１，７０２は位相回転量検出器
２０７の二つの入力端子、７０３は関数発生器の
振幅を表わす信号の入力端子、７０４は関数発生
器の出力端子、７０５は90゜移相器、７０６は掛
算器、７０７は切替スイツチ、I1〜Ioは積分器を
表わす。
Fig. 1 is a diagram showing an example of input/output characteristics of a nonlinear amplifier, Fig. 2 is a diagram showing a first embodiment according to the present invention, and Fig. 3 is a diagram showing data points of a 16QAM signal and AM
FIG. 4 is a diagram showing the second embodiment of the present invention; FIG. 5 is a diagram showing an example of the product detector in FIG. 2; FIG. 6 is a diagram showing data points subjected to PM conversion; FIG. 7 is a diagram showing an example of the configuration of the controller in FIG. 2, FIG. 7 is a diagram showing another example of the configuration of the controller and function generator in FIG. FIG. 3 is a diagram showing final input signal amplitude versus phase characteristics. In the figure, 201 is a signal input terminal, 202 is a phase controller, 203 is a reference carrier generator, 205 is a discriminator, 206 is a demodulated signal output terminal, 207 is a phase rotation amount detector, 208 is a function generator, 209 is an envelope detector, 501 and 502 are orthogonal product detectors,
Two input terminals 204, 503, 507 are multiplicative detectors, 504, 508 are filters, 601, 6
02 are two input terminals of the phase rotation amount detector 207, 603 is an output terminal of the phase rotation amount detector 207, 604 is a 90° phase shifter, 605 is a multiplier, 60
6 is an integrator, 701 and 702 are two input terminals of the phase rotation amount detector 207, 703 is an input terminal for a signal representing the amplitude of the function generator, 704 is an output terminal of the function generator, and 705 is a 90° phase shift 706 is a multiplier, 707 is a changeover switch, and I 1 to I o are integrators.
Claims (1)
いて、 前記入力信号の位相を制御信号によつて制御す
る位相制御器と、 前記位相制御器の出力と一定の振幅及び周波数
を有する参照用搬送波とから前記位相制御器の出
力の振幅と前記搬送波に対する第１の位相差とを
検波する検波器と、 前記検波器の出力振幅及び第１の位相差を所定
のしきい値と比較し、所定の多値多相信号を出力
する識別器と、 前記識別器の出力信号の位相と前記検波器の出
力信号の位相との第２の位相差を電圧で示した第
２の位相差信号を発生する位相回転量検出器と、 前記入力信号の振幅を検出する包絡線検波器
と、 前記位相差信号を前記識別器の出力信号の振幅
に応じて個別に積分する積分回路と前記包絡線検
波器の出力信号の振幅に応じて前記積分回路の出
力を選択し前記位相制御器に制御信号として供給
する回路とを有する関数発生器と を含み、前記位相制御器は前記制御信号の振幅に
応じて前記入力信号の位相を制御することにより
前記第２の位相差を０にすることを特徴とする復
調回路。[Scope of Claims] 1. A demodulation circuit for an input signal subjected to multilevel polyphase modulation, comprising: a phase controller that controls the phase of the input signal by a control signal; and an output of the phase controller that has a constant amplitude and a detector that detects the amplitude of the output of the phase controller and a first phase difference with respect to the carrier wave from a reference carrier wave having a frequency; a discriminator that outputs a predetermined multivalued multiphase signal, and a second phase difference between the phase of the output signal of the discriminator and the phase of the output signal of the detector, expressed as a voltage. a phase rotation amount detector that generates a phase difference signal; an envelope detector that detects the amplitude of the input signal; and an integration circuit that individually integrates the phase difference signal according to the amplitude of the output signal of the discriminator. and a function generator having a circuit that selects the output of the integrating circuit according to the amplitude of the output signal of the envelope detector and supplies it to the phase controller as a control signal. A demodulation circuit characterized in that the second phase difference is made zero by controlling the phase of the input signal according to the amplitude of the signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2586979A JPS55118212A (en) | 1979-03-06 | 1979-03-06 | Demodulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2586979A JPS55118212A (en) | 1979-03-06 | 1979-03-06 | Demodulation circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55118212A JPS55118212A (en) | 1980-09-11 |
| JPH0125259B2 true JPH0125259B2 (en) | 1989-05-17 |
Family
ID=12177789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2586979A Granted JPS55118212A (en) | 1979-03-06 | 1979-03-06 | Demodulation circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55118212A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1251082B (en) * | 1991-07-11 | 1995-05-04 | Sits Soc It Telecom Siemens | PROCEDURE FOR THE COMPENSATION OF THE AM / PM DISTORTION OF A TRANSMITTER THROUGH MODULATION OF THE PHASE OF THE GLOCAL OSCILLATION, AND RELATED CIRCUIT OF COMPEMSATION. |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50116205A (en) * | 1974-02-26 | 1975-09-11 | ||
| JPS5295908A (en) * | 1976-02-06 | 1977-08-12 | Nec Corp | Adaptable carrier phase control device |
-
1979
- 1979-03-06 JP JP2586979A patent/JPS55118212A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50116205A (en) * | 1974-02-26 | 1975-09-11 | ||
| JPS5295908A (en) * | 1976-02-06 | 1977-08-12 | Nec Corp | Adaptable carrier phase control device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55118212A (en) | 1980-09-11 |
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