JPH0583310A - Automatic frequency control circuit - Google Patents
Automatic frequency control circuitInfo
- Publication number
- JPH0583310A JPH0583310A JP3240718A JP24071891A JPH0583310A JP H0583310 A JPH0583310 A JP H0583310A JP 3240718 A JP3240718 A JP 3240718A JP 24071891 A JP24071891 A JP 24071891A JP H0583310 A JPH0583310 A JP H0583310A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- carrier
- circuit
- output
- multiplier
- 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.)
- Pending
Links
Landscapes
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、自動周波数制御回路に
関し、特にディジタル衛星通信の受信装置に使用される
自動周波数制御回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic frequency control circuit, and more particularly to an automatic frequency control circuit used in a receiver for digital satellite communication.
【0002】[0002]
【従来の技術】従来の自動周波数制御(以下AFCとい
う)回路は、図2に示されるように、受信信号として変
調信号と同時に送られてくるパイロット信号を乗算器2
2と電圧制御発振器(以下VCOという)21で復調
し、パイロット信号の基準となる局部発振信号と比較
し、その差を打ち消すようにVCO21を制御して、本
来のベースバンド信号の周波数を補正していた。図2の
従来のAFC回路は、制御電圧によって発振周波数が変
化する電圧制御発振器(VCO)21と、受信信号とV
COの出力を乗算する乗算器22と、パイロット信号の
周波数を通過させる帯域通過フィルタ23と、受信側の
パイロット信号の基準となる局部発振器24と、パイロ
ット信号と基準局部発振信号を比較する位相比較器25
と、位相比較器25の出力をフィルタリングしてVCO
21への帰還位相を合わせるループ・フィルタ26から
構成される。したがって送信側は変調信号と同時にパイ
ロット信号を送信し、受信側は変調信号とパイロット信
号とを受信し、パイロット信号を局部発振器24が出力
するパイロット信号と同等の基準局部発振信号と位相比
較器25で比較しその差を打ち消すようにVCO21を
制御して受信信号の周波数を補正する。受信信号のベー
スバンド信号は制御されたVCO21の出力でベースバ
ンド信号の周波数を変換するので、ベースバンド信号の
周波数も同様に補正され復調器28には周波数偏差が補
償された送り側のベースバンドが取り出されていた。2. Description of the Related Art In a conventional automatic frequency control (hereinafter referred to as AFC) circuit, as shown in FIG. 2, a pilot signal sent at the same time as a modulated signal as a received signal is multiplied by a multiplier 2
2 and a voltage controlled oscillator (hereinafter referred to as VCO) 21 to demodulate, compare with a local oscillation signal that serves as a reference of a pilot signal, control the VCO 21 to cancel the difference, and correct the frequency of the original baseband signal. Was there. The conventional AFC circuit shown in FIG. 2 has a voltage-controlled oscillator (VCO) 21 whose oscillation frequency changes according to a control voltage, a received signal and a VCO.
A multiplier 22 that multiplies the output of CO, a bandpass filter 23 that passes the frequency of a pilot signal, a local oscillator 24 that serves as a reference for a pilot signal on the receiving side, and a phase comparison that compares the pilot signal with a reference local oscillation signal. Bowl 25
And the output of the phase comparator 25 is filtered to
It is composed of a loop filter 26 for adjusting the feedback phase to 21. Therefore, the transmitting side transmits the pilot signal at the same time as the modulated signal, the receiving side receives the modulated signal and the pilot signal, and the pilot signal is equivalent to the reference local oscillation signal and the phase comparator 25 which are equivalent to the pilot signal output from the local oscillator 24. Then, the VCO 21 is controlled so as to cancel the difference and the frequency of the received signal is corrected. Since the baseband signal of the received signal converts the frequency of the baseband signal by the output of the controlled VCO 21, the frequency of the baseband signal is similarly corrected and the demodulator 28 is compensated for the frequency deviation, and the baseband on the sending side is compensated. Had been taken out.
【0003】[0003]
【発明が解決しようとする課題】この従来のAFC回路
は、変調信号に加えて周波数補正用のパイロット信号を
送受する装置が必要である。したがって単一衛星中継器
で少数の回線の場合でも、送信側受信側にパイロット信
号用装置を備えなければならないので、必要とする少数
の回線伝送データ信号に対して装備されるパイロット信
号分の利用効率が低くなる欠点があった。The conventional AFC circuit requires a device for transmitting and receiving a pilot signal for frequency correction in addition to the modulation signal. Therefore, even if a single satellite repeater has a small number of lines, it is necessary to equip the transmitter and receiver with a pilot signal device. It had the drawback of being less efficient.
【0004】[0004]
【課題を解決するための手段】本発明の自動周波数制御
回路は、PSK変調信号等の受信信号をN逓倍するN逓
倍回路と、このN(Nは2以上の整数)逓倍回路の出力
周波数と等しい信号を発生する電圧制御発振器と、前記
N逓倍回路の出力信号と前記電圧制御発振器の出力信号
とを比較する位相比較器と、この位相比較器から出力さ
れる不要な成分を除去し前記電圧制御発振器に位相制御
電圧を供給するループフィルタと、前記電圧制御発振器
の出力信号をN分周するN分周回路と、前記受信信号と
前記N分周回路の出力信号とを乗算する乗算器と、この
乗算器が出力する変調信号を復調する復調器とを備えて
いる。SUMMARY OF THE INVENTION An automatic frequency control circuit of the present invention comprises an N multiplication circuit for multiplying a received signal such as a PSK modulated signal by N, and an output frequency of the N (N is an integer of 2 or more) multiplication circuit. A voltage controlled oscillator that generates equal signals, a phase comparator that compares the output signal of the N multiplication circuit and the output signal of the voltage controlled oscillator, and an unnecessary component that is output from the phase comparator to remove the unnecessary voltage. A loop filter for supplying a phase control voltage to a controlled oscillator, an N divider for dividing an output signal of the voltage controlled oscillator by N, and a multiplier for multiplying the received signal by an output signal of the N divider. , And a demodulator that demodulates the modulated signal output from this multiplier.
【0005】[0005]
【実施例】次に本発明について図面を参照して説明す
る。図1は本発明の一実施例のブロック図である。図1
の実施例は、受信信号をN逓倍するN逓倍回路1と、制
御電圧によって出力周波数が変化し、N逓倍された受信
信号の周波数とほぼ等しい信号を発生する電圧制御発振
器(VCO)2と、N逓倍回路1の出力信号とVCO2
の出力信号とを比較する位相比較器3と、位相比較器3
から出力される不要な成分を除去し、VCO2へのルー
プ位相を合わせた制御電圧を出力するループ・フィルタ
4と、VCO2の出力信号をN分周するN分周回路5
と、受信信号とVCO2の出力をN分周した信号を乗算
する乗算器6と、乗算器6に入力された受信信号とN分
周回路5の出力信号とを乗算し復調する復調器7とから
構成される。The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. Figure 1
In this embodiment, an N multiplication circuit 1 that multiplies a received signal by N, a voltage controlled oscillator (VCO) 2 that generates a signal whose output frequency is changed by a control voltage and is approximately equal to the frequency of the N multiplied reception signal, Output signal of N multiplication circuit 1 and VCO2
And a phase comparator 3 for comparing the output signal of
A loop filter 4 that removes unnecessary components output from the VCO 2 and outputs a control voltage that matches the loop phase to the VCO 2, and an N divider circuit 5 that divides the output signal of the VCO 2 by N
A multiplier 6 that multiplies the received signal by a signal obtained by dividing the output of the VCO 2 by N, and a demodulator 7 that multiplies the received signal input to the multiplier 6 by the output signal of the N divider circuit 5 and demodulates. Composed of.
【0006】次に本実施例の動作を説明する。受信信号
は、N逓倍されて変調成分が取り除かれる。例えば2相
PSK受信信号の場合には、2逓倍すると受信周波数の
2倍である無変調の搬送波成分が得られる。N逓倍され
た搬送波信号は位相比較器3でVCO2の出力信号と比
較され位相差を検出した出力は、ループ・フィルタ4を
通してVCO2を制御する。位相比較器3,ループ・フ
ィルタ4,VCO2で形成する位相同期ループは、N逓
倍の搬送波成分に追従し、受信信号のN倍である周波数
成分の搬送波信号を再生する。再生された搬送波をN分
周回路5でN分周することにより元の受信信号に対応す
る位相のあった搬送波が得られる。この搬送波信号と受
信信号を乗算すると、復調器7の出力には、周波数補正
された搬送波信号で復調するので、正しいベースバンド
信号が得られる。Next, the operation of this embodiment will be described. The received signal is multiplied by N to remove the modulation component. For example, in the case of a two-phase PSK reception signal, if it is multiplied by 2, an unmodulated carrier component that is twice the reception frequency is obtained. The carrier wave signal multiplied by N is compared with the output signal of the VCO 2 by the phase comparator 3, and the output whose phase difference is detected controls the VCO 2 through the loop filter 4. The phase-locked loop formed by the phase comparator 3, the loop filter 4, and the VCO 2 follows the N-fold carrier component and reproduces the carrier signal of the frequency component N times the received signal. By dividing the reproduced carrier wave by N by the N frequency divider circuit 5, a carrier wave having a phase corresponding to the original received signal can be obtained. When this carrier signal is multiplied by the received signal, the output of the demodulator 7 is demodulated by the frequency-corrected carrier signal, so that a correct baseband signal can be obtained.
【0007】[0007]
【発明の効果】以上説明したように本発明は、受信信号
をN逓倍して位相同期ループによってN倍の周波数成分
である搬送波再生回路と、N分周回路とから得られる基
準搬送波と受信信号との乗算器とを備えることにより、
従来例のような周波数を補正するためのパイロット信号
用の送受信装置が不要になる効果を有する。As described above, according to the present invention, the received signal is multiplied by N, and the reference carrier and the received signal obtained from the carrier recovery circuit, which is the frequency component of N times by the phase locked loop, and the N divider circuit. By including a multiplier with
This has the effect of eliminating the need for a transmitter / receiver for pilot signals for frequency correction as in the conventional example.
【図1】本発明の一実施例のブロック図である。FIG. 1 is a block diagram of an embodiment of the present invention.
【図2】従来のAFC回路のブロック図である。FIG. 2 is a block diagram of a conventional AFC circuit.
【符号の説明】 1 N逓倍回路 2,21 電圧制御発振器(VCO) 3,25 位相比較器 4,26 ループ・フィルタ 5 N分周回路 6,22 乗算器 7,28 復調器 23,27 帯域通過フィルタ 24 局部発振器[Explanation of Codes] 1 N multiplier circuit 2,21 Voltage controlled oscillator (VCO) 3,25 Phase comparator 4,26 Loop filter 5 N divider circuit 6,22 Multiplier 7,28 Demodulator 23,27 Bandpass Filter 24 Local oscillator
Claims (2)
るN逓倍回路と、このN(Nは2以上の整数)逓倍回路
の出力周波数と等しい信号を発生する電圧制御発振器
と、前記N逓倍回路の出力信号と前記電圧制御発振器の
出力信号とを比較する位相比較器と、この位相比較器か
ら出力される不要な成分を除去し前記電圧制御発振器に
位相制御電圧を供給するループフィルタと、前記電圧制
御発振器の出力信号をN分周するN分周回路と、前記受
信信号と前記N分周回路の出力信号とを乗算する乗算器
と、この乗算器が出力する変調信号を復調する復調器と
を備えていることを特徴とする自動周波数制御回路。1. An N multiplier circuit for multiplying a received signal such as a PSK modulated signal by N, a voltage controlled oscillator for generating a signal equal to the output frequency of the N (N is an integer of 2 or more) multiplier circuit, and the N multiplier circuit. A phase comparator that compares the output signal of the circuit and the output signal of the voltage controlled oscillator, a loop filter that removes unnecessary components output from the phase comparator and supplies a phase control voltage to the voltage controlled oscillator, An N divider for dividing the output signal of the voltage controlled oscillator by N, a multiplier for multiplying the received signal by the output signal of the N divider, and a demodulator for demodulating the modulated signal output by the multiplier And an automatic frequency control circuit.
記N逓倍回路でN逓倍されることにより、前記受信信号
に含まれる変調信号成分が除去される作用を含んでいる
ことを特徴とする請求項1記載の自動周波数制御回路。2. The PSK modulation signal, which is the received signal, is multiplied by N in the N multiplication circuit, so that the modulation signal component included in the received signal is removed. Item 1. The automatic frequency control circuit according to item 1.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3240718A JPH0583310A (en) | 1991-09-20 | 1991-09-20 | Automatic frequency control circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3240718A JPH0583310A (en) | 1991-09-20 | 1991-09-20 | Automatic frequency control circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0583310A true JPH0583310A (en) | 1993-04-02 |
Family
ID=17063675
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3240718A Pending JPH0583310A (en) | 1991-09-20 | 1991-09-20 | Automatic frequency control circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0583310A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8607767B2 (en) | 2006-05-29 | 2013-12-17 | Mahle International Gmbh | Device for ventilating a crankcase |
US11598234B2 (en) | 2018-05-31 | 2023-03-07 | Yanmar Power Technology Co., Ltd. | Breather device and engine |
-
1991
- 1991-09-20 JP JP3240718A patent/JPH0583310A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8607767B2 (en) | 2006-05-29 | 2013-12-17 | Mahle International Gmbh | Device for ventilating a crankcase |
US11598234B2 (en) | 2018-05-31 | 2023-03-07 | Yanmar Power Technology Co., Ltd. | Breather device and engine |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20010321 |