JPH05236042A - Mis-synchronization preventing device - Google Patents
Mis-synchronization preventing deviceInfo
- Publication number
- JPH05236042A JPH05236042A JP4032038A JP3203892A JPH05236042A JP H05236042 A JPH05236042 A JP H05236042A JP 4032038 A JP4032038 A JP 4032038A JP 3203892 A JP3203892 A JP 3203892A JP H05236042 A JPH05236042 A JP H05236042A
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- 238000001514 detection method Methods 0.000 claims abstract description 23
- 230000005540 biological transmission Effects 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims description 16
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 238000004891 communication Methods 0.000 claims description 6
- 230000006835 compression Effects 0.000 claims 2
- 238000007906 compression Methods 0.000 claims 2
- 238000007493 shaping process Methods 0.000 claims 2
- 230000002265 prevention Effects 0.000 claims 1
- 230000001360 synchronised effect Effects 0.000 abstract description 9
- 238000009499 grossing Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 238000007476 Maximum Likelihood Methods 0.000 description 1
- 108010076504 Protein Sorting Signals Proteins 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
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- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は入力周波数変動が変調速
度に比して大きなシステムにおける受信方式に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving system in a system in which fluctuations in input frequency are large compared to the modulation rate.
【０００２】[0002]
【従来の技術】衛星通信等で受信変調波信号が変調速度
に比して大きい場合信号捕捉用の周波数スイープ回路を
用いて、信号捕捉を行うのが通常である。この信号の捕
捉において正しく信号を捕捉したかどうかを判定するた
めには復調された信号列を用いて判断する必要がある。
ここでは、変調信号中にフレーム同期信号が挿入されて
いる場合について説明する。又、変調方式については２
相ＰＳＫ信号を用いて説明する。2. Description of the Related Art In satellite communication or the like, when the received modulated wave signal is larger than the modulation speed, it is usual to perform signal acquisition using a frequency sweep circuit for signal acquisition. In this signal capture, it is necessary to make a determination using the demodulated signal sequence in order to determine whether or not the signal has been captured correctly.
Here, a case where a frame synchronization signal is inserted in the modulated signal will be described. Also, regarding the modulation method, 2
This will be described using the phase PSK signal.
【０００３】入力信号は電圧制御可変の発振器で駆動さ
れる周波数変換回路に入力され新たな中間周波数帯に変
換される。この電圧制御発振器の制御手段については後
述する。新たな中間周波数帯の変調信号は復調器に入力
され同期復調される。復調された信号は信号に挿入され
ているフレーム同期信号を検出するためのフレーム同期
回路に入力される。フレーム同期回路はフレーム同期信
号は既知であるため一般に相関器にて構成される。The input signal is input to a frequency conversion circuit driven by a voltage controlled variable oscillator and converted into a new intermediate frequency band. The control means of this voltage controlled oscillator will be described later. The new intermediate frequency band modulated signal is input to the demodulator and synchronously demodulated. The demodulated signal is input to the frame synchronization circuit for detecting the frame synchronization signal inserted in the signal. Since the frame synchronization signal is already known, the frame synchronization circuit is generally composed of a correlator.
【０００４】同期の確実性をきすためにフレーム同期回
路は非同期状態から同期状態への移行のための後方保護
手順、同期状態から非同期状態に移行するための前方保
護手順を用いるのが通常である。この保護回路の定数は
最悪の回線状態における復調器出力の誤りに耐えられる
ように選ばれる。通常は誤り率０．０１程度でも同期が
正しく行われる様に設計されている。In order to reduce the certainty of synchronization, the frame synchronization circuit normally uses a backward protection procedure for transition from an asynchronous state to a synchronous state and a forward protection procedure for transition from a synchronous state to an asynchronous state. .. The constants of this protection circuit are chosen to withstand the error in the demodulator output under worst case line conditions. Normally, it is designed so that synchronization can be performed correctly even when the error rate is about 0.01.
【０００５】前記電圧制御発振器はフレーム同期回路が
同期宣言をするまで定められた手順でその発振周波数を
変化させ、あらかじめ想定される入力周波数範囲以上を
スイープする。The voltage controlled oscillator changes its oscillation frequency in a predetermined procedure until the frame synchronization circuit declares synchronization, and sweeps over an input frequency range which is assumed in advance.
【０００６】ひとたび、フレーム同期回路が同期宣言を
行ったときこの発振器は周波数スイープを停止し信号捕
捉が完了する。Once the frame synchronization circuit has declared synchronization, this oscillator stops the frequency sweep and signal acquisition is completed.
【０００７】[0007]
【発明が解決しようとする課題】ところが、入力周波数
変動が変調速度に比して大きいとき（或いは極めて低レ
ートの速度の信号を伝送しようとする時）以下のような
不具合が発生する。However, when the input frequency fluctuation is large compared to the modulation speed (or when an extremely low rate signal is transmitted), the following problems occur.
【０００８】２相ＰＳＫ信号を考えたとき変調信号の搬
送波周波数に一致した再生搬送波で復調した場合は当然
の事ながら正しい信号が復調される。ところが復調器入
力信号が変調波の中心周波数よりちょうど変調速度だけ
ずれていた場合を考える。When a two-phase PSK signal is considered, if a demodulation is performed with a reproduced carrier that matches the carrier frequency of the modulated signal, a correct signal is naturally demodulated. However, consider the case where the demodulator input signal deviates from the center frequency of the modulated wave by exactly the modulation speed.
【０００９】変調速度をｆs とするとＴ（＝１／ｆs ）
の間で復調器の再生搬送波と入力変調波との位相関係は ２π＊ｆs ＊Ｔ＝２π＊ｆs ＊１／ｆs ＝２π （１） となり、復調器自身は正しい搬送波で復調している時と
同じ状態になる。これが一般に言われる復調器の誤同期
の現象である。When the modulation speed is f s , T (= 1 / f s )
The phase relationship between the input modulated wave with regenerated carrier of the demodulator between 2π * f s * T = 2π * f s * 1 / f s = 2π (1) , and the demodulator itself demodulates the correct carrier It will be the same as when you are. This is a generally called phenomenon of demodulator missynchronization.
【００１０】この時の、復調器から出力される復調デー
タは正しく復調した場合と全く同一になるため復調器に
後続するフレーム同期回路も通常の様に同期宣言を行っ
てしまう。At this time, the demodulated data output from the demodulator is exactly the same as that when the demodulator is correctly demodulated, so that the frame synchronization circuit subsequent to the demodulator also declares synchronization as usual.
【００１１】勿論、復調器には変調波信号に対応した受
信フィルターが備えられているため、復調信号自身の受
信フィルターによる歪はかなり存在する。しかしなが
ら、通信路の状態が極めて良く殆ど雑音が無視できる場
合、或いはフレーム同期回路の持つ後方・前方保護のた
めに十分にフレーム同期は保たれてしまう。Of course, since the demodulator is provided with a reception filter corresponding to the modulated wave signal, there is considerable distortion of the demodulation signal itself due to the reception filter. However, when the condition of the communication path is extremely good and almost no noise is negligible, or the frame synchronization is sufficiently maintained due to the backward / forward protection of the frame synchronization circuit.
【００１２】従って、伝送路で生じる周波数変動が変調
速度に比して極めて大きな系では周波数スイープによる
信号捕捉法はシステムの動作を不安定にし、安定なシス
テムを構築する事ができなかった。Therefore, in a system in which the frequency fluctuation occurring in the transmission line is extremely large compared to the modulation speed, the signal acquisition method by frequency sweep makes the operation of the system unstable and a stable system cannot be constructed.
【００１３】[0013]
【課題を解決するための手段】本発明は、この様な現象
を除くために従来回路に受信フィルター出力信号の電力
を求め、変調方式に対応して復調器が擬似同期を行う可
能性のある周波数の点を全て調べ、その内で最大電力を
有する周波数の点を正しい点とみなす最尤方式である。According to the present invention, in order to eliminate such a phenomenon, the power of the reception filter output signal is obtained in the conventional circuit, and there is a possibility that the demodulator may perform pseudo synchronization depending on the modulation method. This is a maximum likelihood method in which all frequency points are examined and the frequency point having the maximum power is regarded as a correct point.
【００１４】[0014]
【実施例】次に本発明の実施例を図面を参照して説明す
る。Embodiments of the present invention will now be described with reference to the drawings.
【００１５】図１に示すとおり、１０１は周波数変換回
路、１０２は受信フィルター、１０３は２相ＰＳＫ復調
器、１０４は同期語検出用フレーム同期回路、１０５は
受信フィルター出力レベルを検出するレベル検出回路、
１０６はスイープ制御回路、１０７は電圧制御発振器で
ある。As shown in FIG. 1, 101 is a frequency conversion circuit, 102 is a receiving filter, 103 is a two-phase PSK demodulator, 104 is a sync word detecting frame synchronizing circuit, and 105 is a level detecting circuit for detecting the receiving filter output level. ,
Reference numeral 106 is a sweep control circuit, and 107 is a voltage controlled oscillator.
【００１６】以下、本発明の第１の実施例を説明する。The first embodiment of the present invention will be described below.
【００１７】受信変調波信号は周波数変換回路１０１に
入力され、電圧制御発振器１０７より供給される信号に
より中間周波数帯に変換される。変換された信号は受信
フィルター１０２に入力された後、２相ＰＳＫ復調器１
０３に入力される。中間周波数が２相復調器の中心周波
数にほぼ等しく、復調器搬送波再生回路の能力内であれ
ば復調は正しく行われる。復調系列は後続のフレーム検
出回路に入力され、正しいデータ列が入力された場合、
フレーム同期が確立する。このフレーム同期確立信号を
基にスイープ制御回路１０６は電圧制御発振器１０７を
制御する。制御の方法はフレーム同期確立が得られない
場合にはスイープ回路出力のスイープ電圧を順次増加、
又は減少させる。ひとたびフレーム同期が確立した場合
にはスイープ制御電圧をその時点で停止させる。以上ま
では従来の方式と同一である。The received modulated wave signal is input to the frequency conversion circuit 101 and converted into an intermediate frequency band by the signal supplied from the voltage controlled oscillator 107. The converted signal is input to the reception filter 102 and then the two-phase PSK demodulator 1
It is input to 03. If the intermediate frequency is approximately equal to the center frequency of the two-phase demodulator and is within the capability of the demodulator carrier recovery circuit, demodulation will be performed correctly. The demodulation sequence is input to the subsequent frame detection circuit, and if the correct data string is input,
Frame synchronization is established. The sweep control circuit 106 controls the voltage controlled oscillator 107 based on the frame synchronization establishment signal. The method of control is to increase the sweep voltage of the sweep circuit output sequentially when frame synchronization cannot be established.
Or reduce. Once frame synchronization is established, the sweep control voltage is stopped at that point. The above is the same as the conventional method.
【００１８】本実施例においては、受信フィルター１０
２の出力レベルを測定するレベル検出回路１０５が従来
例に追加される。このレベル検出回路１０５の構成につ
いては様々な方式があるため言及しないが、最も簡単な
構成としてはダイオード検波器と検波後に生ずる高周波
成分を平滑する平滑回路とで構成できる。In the present embodiment, the reception filter 10
A level detection circuit 105 that measures the output level of 2 is added to the conventional example. The structure of the level detection circuit 105 will not be described because there are various methods, but the simplest structure can be composed of a diode detector and a smoothing circuit for smoothing high frequency components generated after detection.
【００１９】スイープの過程においてフレーム同期回路
１０４がフレーム同期を宣言したとき、スイープ制御回
路１０６はスイープを停止すると共にレベル検出回路１
０５を用いて受信フィルター１０２の出力レベルを測定
する。そして、その測定値を記憶し再びスイープを開始
し、次に再びフレーム同期が確立するまでスイープを継
続する。When the frame synchronization circuit 104 declares frame synchronization in the sweep process, the sweep control circuit 106 stops the sweep and the level detection circuit 1
05 is used to measure the output level of the reception filter 102. Then, the measured value is stored, the sweep is started again, and the sweep is continued until the frame synchronization is established again.
【００２０】再びフレーム同期確立信号をフレーム同期
回路１０４より受けた時、そのスイープ電圧が前回のフ
レーム同期確立の時の電圧と異なっていれば、再びレベ
ル検出回路１０５の出力信号を測定する。もし、前回の
スイープ電圧に一致していればレベル検出は行わない。
この様にしてスイープ制御回路１０６がスイープすべき
範囲を全てスイープし、前記と同様の操作を全スイープ
範囲について行う。When the frame synchronization signal is received again from the frame synchronization circuit 104, if the sweep voltage is different from the voltage at the previous frame synchronization establishment, the output signal of the level detection circuit 105 is measured again. If it matches the previous sweep voltage, level detection is not performed.
In this way, the sweep control circuit 106 sweeps the entire range to be swept, and the same operation as described above is performed for the entire sweep range.
【００２１】前に述べたように、復調器の誤同期は変調
速度周波数に対応して発生するため、レベル検出回路１
０５の出力は正規に復調器が同期した場合に比べて、誤
同期時は受信フィルター１０２の中心帯域とかなり離れ
ているために小さな値となる。特に通信システムで抑止
されているフィルターの構成法としてナイキストフィル
ターを用いた場合には受信フィルター１０２の３ｄＢ帯
域は中心周波数に対して変調周波数の１／２となるか
ら、変調速度だけ離れた信号の受信フィルター出力レベ
ルはかなり小さくなる事が容易に類推できる。As described above, since the false synchronization of the demodulator occurs in correspondence with the modulation speed frequency, the level detection circuit 1
The output of 05 has a small value as compared with the case where the demodulator is normally synchronized, because it is far from the center band of the reception filter 102 at the time of incorrect synchronization. In particular, when a Nyquist filter is used as a method of constructing a filter that is suppressed in a communication system, the 3 dB band of the reception filter 102 becomes 1/2 of the modulation frequency with respect to the center frequency, so that a signal separated by the modulation speed is used. It can be easily inferred that the output level of the reception filter becomes considerably small.
【００２２】従って、スイープ制御回路１０６は全スイ
ープ域に渡って発生したフレーム同期確立の制御電圧点
において、対応した検出レベルを比較しその最大レベル
を示したスイープ電圧を再び電圧制御発振器に与える事
により正しい復調器の同期を確立でき誤同期を防止でき
る。Therefore, the sweep control circuit 106 compares the detection levels corresponding to each other at the control voltage points for establishing frame synchronization generated over the entire sweep range, and again applies the sweep voltage showing the maximum level to the voltage controlled oscillator. As a result, correct demodulator synchronization can be established and false synchronization can be prevented.
【００２３】又、伝送路の雑音が大きくなってきて、周
波数ズレに対する受信フィルター出力のレベル差がさほ
どつかなくなる場合においては復調器の誤同期は発生し
なくなり、誤動作も生じない。Further, when the noise on the transmission line becomes large and the level difference of the output of the reception filter with respect to the frequency shift becomes small, the erroneous synchronization of the demodulator does not occur and the erroneous operation does not occur.
【００２４】次に本発明の第２の実施例を説明する。Next, a second embodiment of the present invention will be described.
【００２５】図１に示すとおり、受信変調波信号は周波
数変換回路１０１に入力され電圧制御発振器１０７より
供給される信号により中間周波数帯に変換される。変換
された信号は受信フィルター１０２に入力された後、２
相ＰＳＫ復調器１０３に入力される。中間周波数が２相
ＰＳＫ復調器１０３の中心周波数にほぼ等しく、復調器
搬送波再生回路の能力内であれば復調は正しく行われ
る。復調系列は後続のフレーム検出回路に入力され、正
しいデータ列が入力された場合、フレーム同期が確立す
る。このフレーム同期確立信号を基にスイープ制御回路
１０６は、電圧制御発振器を制御する。制御の方法はフ
レーム同期確立が得られない場合にはスイープ回路出力
のスイープ電圧を順次増加、又は減少させる。ひとたび
フレーム同期が確立した場合にはスイープ制御電圧をそ
の時点で停止させる。以上までは従来の方式と同一であ
る。As shown in FIG. 1, the received modulated wave signal is input to the frequency conversion circuit 101 and converted into an intermediate frequency band by the signal supplied from the voltage controlled oscillator 107. The converted signal is input to the reception filter 102 and then 2
It is input to the phase PSK demodulator 103. If the intermediate frequency is approximately equal to the center frequency of the two-phase PSK demodulator 103 and is within the capability of the demodulator carrier recovery circuit, demodulation is performed correctly. The demodulation sequence is input to the subsequent frame detection circuit, and when the correct data string is input, frame synchronization is established. The sweep control circuit 106 controls the voltage controlled oscillator based on the frame synchronization establishment signal. The control method sequentially increases or decreases the sweep voltage of the sweep circuit output when the frame synchronization cannot be established. Once frame synchronization is established, the sweep control voltage is stopped at that point. The above is the same as the conventional method.
【００２６】本実施例においては、受信フィルター１０
２の出力レベルを測定するレベル検出回路１０５が従来
例に追加される。このレベル検出器の構成については様
々な方式があるため言及しないが、最も簡単な構成とし
てはダイオード検波器と検波後に生ずる高周波成分を平
滑する平滑回路とで構成できる。In the present embodiment, the reception filter 10
A level detection circuit 105 that measures the output level of 2 is added to the conventional example. The structure of this level detector will not be described because there are various methods, but the simplest structure can be composed of a diode detector and a smoothing circuit for smoothing high frequency components generated after detection.
【００２７】スイープの過程においてフレーム同期回路
１０４がフレーム同期を宣言したとき、スイープ制御回
路１０６はスイープを停止すると共にレベル検出回路１
０５を用いて受信フィルターの出力レベルを測定する。
そして、その測定値を記憶する。When the frame synchronization circuit 104 declares frame synchronization during the sweep process, the sweep control circuit 106 stops the sweep and the level detection circuit 1
05 is used to measure the output level of the reception filter.
Then, the measured value is stored.
【００２８】誤同期の発生する周波数は変調速度と対応
している。本例では正規周波数に対して±変調速度周波
数の２点である。従って最初に同期した点が誤同期点か
正しい同期点かは不明であるが、復調器の同期する点が
本例の様に３点であれば現在の周波数を規準にして±変
調速度の分だけずれた周波数の点に電圧制御発振器１０
７を設定する。そして、これらの周波数点で再びフレー
ム同期が取れれば対応するレベル検出回路１０５の出力
レベルを測定し記憶する。The frequency at which false synchronization occurs corresponds to the modulation speed. In this example, there are two points of ± modulation speed frequency with respect to the normal frequency. Therefore, it is unclear whether the first synchronized point is a false synchronized point or a correct synchronized point, but if there are three synchronized points of the demodulator as in this example, the current frequency is used as a reference and the ± modulation speed is divided. The voltage controlled oscillator 10
Set 7. Then, if frame synchronization is obtained again at these frequency points, the output level of the corresponding level detection circuit 105 is measured and stored.
【００２９】スイープ制御回路１０６は、これらの周波
数点に対応するレベル検出器１０５の出力レベルを比較
し最大のレベルを示す点を正規の周波数として設定す
る。The sweep control circuit 106 compares the output levels of the level detector 105 corresponding to these frequency points and sets the point showing the maximum level as the normal frequency.
【００３０】前に述べたように、復調器の誤同期は変調
速度周波数に対応して発生するため、レベル検出回路１
０５の出力は正規に復調器が同期した場合に比べて、誤
同期時は受信フィルター１０２の中心帯域とかなり離れ
ているために小さな値となる。特に通信システムで抑止
されているフィルターの構成法としてナイキストフィル
ターを用いた場合には受信フィルターの３ｄＢ帯域は中
心周波数に対して変調周波数の１／２となるから、変調
速度だけ離れた信号の受信フィルター出力レベルはかな
り小さくなる事が容易に類推できる。As mentioned above, since the false synchronization of the demodulator occurs corresponding to the modulation speed frequency, the level detection circuit 1
The output of 05 has a small value as compared with the case where the demodulator is normally synchronized, because it is far from the center band of the reception filter 102 at the time of incorrect synchronization. In particular, when a Nyquist filter is used as a method of constructing a filter that is suppressed in a communication system, the 3 dB band of the reception filter is half the modulation frequency with respect to the center frequency, so reception of a signal separated by the modulation speed is performed. It can be easily inferred that the filter output level will be quite small.
【００３１】従って、この様にして設定した周波数は正
規の周波数になり、正しい復調器の同期を確立でき誤同
期を防止できる。Therefore, the frequency set in this way becomes a normal frequency, and correct demodulator synchronization can be established and false synchronization can be prevented.
【００３２】又、伝達路の雑音が大きくなってきて、周
波数ズレに対する受信フィルター出力レベル差がさほど
つかなくなる場合においては復調器の誤同期は発生しな
くなり、誤動作も生じない。Further, when the noise on the transmission path becomes large and the difference in the output levels of the reception filter with respect to the frequency shift becomes small, erroneous synchronization of the demodulator does not occur and erroneous operation does not occur.
【００３３】[0033]
【発明の効果】以上説明したように、本発明によれば伝
送路の周波数変動が変調速度に比して大きくスイープ操
作が必要な場合でも、復調器の本質的な特性である誤同
期を防止する事ができる。As described above, according to the present invention, even when the frequency fluctuation of the transmission line is large compared to the modulation speed and the sweep operation is required, the erroneous synchronization which is an essential characteristic of the demodulator is prevented. You can do it.
【図１】本発明の一実施例。FIG. 1 shows an embodiment of the present invention.
１０１ 周波数変換回路 １０２ 受信フィルター １０３ ２相ＰＳＫ復調器 １０４ フレーム同期回路 １０５ レベル検出回路 １０６ スイープ制御回路 １０７ 電圧制御発振器 101 frequency conversion circuit 102 reception filter 103 two-phase PSK demodulator 104 frame synchronization circuit 105 level detection circuit 106 sweep control circuit 107 voltage controlled oscillator
Claims (2)
比較的に小さく、且つ信号中にフレーム信号が挿入され
ている通信システムに用いられる誤同期防止装置におい
て、 入力変調波信号を受けて、電圧制御発振器により、前記
変調波信号を中間周波数帯に変換する周波数変換回路
と、 該周波数変換回路出力信号を入力とし変調信号に対応し
た波形成形及び雑音の圧縮を計る受信フィルターと、 該受信フィルター出力信号を入力とし変調波信号を同期
復調する復調回路と、 該復調回路出力の復調信号を入力とし、前記フレーム信
号に対しフレーム同期を取るフレーム同期回路と、 前記受信フィルター出力のレベルを検出するレベル検出
回路と、 前記フレーム同期より復調器の同期状態を受け、且つ前
記受信レベル検出回路出力信号を入力とするスイープ制
御回路と、 該スイープ制御回路により周波数制御される前記電圧制
御発振器とを有し、前記スイープ制御回路がスイープす
べき全ての周波数範囲において、前記フレーム同期回路
のフレーム同期確立した周波数全てに対応する前記受信
レベル検出回路出力で最大のレベルを示す周波数を正し
い周波数と判断することを特徴とする誤同期防止装置。1. An erroneous synchronization preventing device used in a communication system in which a transmission rate is relatively small with respect to a frequency fluctuation of a transmission line and a frame signal is inserted in the signal, and the input modulation wave signal is received. A frequency conversion circuit for converting the modulated wave signal into an intermediate frequency band by a voltage controlled oscillator; a reception filter for inputting an output signal of the frequency conversion circuit to perform waveform shaping and noise compression corresponding to the modulation signal; A demodulation circuit that receives a filter output signal as input and synchronously demodulates a modulated wave signal, a frame synchronization circuit that receives the demodulation signal of the output of the demodulation circuit as input, and establishes frame synchronization with the frame signal, and detects the level of the reception filter output A level detection circuit for receiving the synchronization state of the demodulator from the frame synchronization, and receiving the output signal of the reception level detection circuit as an input. The sweep control circuit, and the voltage controlled oscillator whose frequency is controlled by the sweep control circuit, and in all frequency ranges to be swept by the sweep control circuit An erroneous synchronization preventing device, characterized in that the frequency showing the maximum level in the corresponding reception level detection circuit output is judged to be a correct frequency.
比較的に小さく、且つ信号中にフレーム信号が挿入され
ている通信システムに用いられる誤同期防止装置におい
て、 入力変調波信号を受けて、電圧制御発振器により、前記
変調波信号を中間周波数帯に変換する周波数変換回路
と、 該周波数変換回路出力信号を入力とし変調信号に対応し
た波形成形及び雑音の圧縮を計る受信フィルターと、 該受信フィルター出力信号を入力とし変調波信号を同期
復調する復調回路と、 該復調回路出力の復調信号を入力とし、前記フレーム信
号に対しフレーム同期を取るフレーム同期回路と、 前記受信フィルター出力のレベルを検出するレベル検出
回路と、 前記フレーム同期より復調器の同期状態を受け、且つ前
記受信レベル検出回路出力信号を入力とするスイープ制
御回路と、 該スイープ制御回路により周波数制御される前記電圧制
御発振器とを有し、 変調方式に対応して正規同期を含めた復調器の同期する
周波数点がＮ（Ｎは正の整数で奇数）個ならば、（Ｎ−
１）÷２の周波数点を最初にフレーム同期が確立された
周波数を規準として上下それぞれに対して行い、それぞ
れの周波数全てに対応する前記受信レベル検出回路出力
で最大のレベルを示す周波数を正しい周波数と判断し前
記電圧制御発振器に設定する復調器誤同期防止装置。2. An erroneous synchronization preventing device used in a communication system in which a transmission rate is relatively small with respect to a frequency fluctuation of a transmission line and a frame signal is inserted in the signal, and the input modulation wave signal is received. A frequency conversion circuit for converting the modulated wave signal into an intermediate frequency band by a voltage controlled oscillator; a reception filter for inputting an output signal of the frequency conversion circuit to perform waveform shaping and noise compression corresponding to the modulation signal; A demodulation circuit that receives a filter output signal as input and synchronously demodulates a modulated wave signal, a frame synchronization circuit that receives the demodulation signal of the output of the demodulation circuit as input, and establishes frame synchronization with the frame signal, and detects the level of the reception filter output A level detection circuit for receiving the synchronization state of the demodulator from the frame synchronization, and receiving the output signal of the reception level detection circuit as an input. A sweep control circuit, and the voltage controlled oscillator whose frequency is controlled by the sweep control circuit. The frequency point of synchronization of the demodulator including normal synchronization corresponding to the modulation method is N (N is a positive integer). If it is an odd number, then (N-
1) ÷ 2 frequency points are performed on the upper and lower sides based on the frequency at which the frame synchronization is first established, and the frequency showing the maximum level at the output of the reception level detection circuit corresponding to all the respective frequencies is the correct frequency. And a demodulator erroneous synchronization prevention device which determines that the voltage controlled oscillator is set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4032038A JP2874703B2 (en) | 1992-02-19 | 1992-02-19 | False synchronization prevention device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4032038A JP2874703B2 (en) | 1992-02-19 | 1992-02-19 | False synchronization prevention device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05236042A true JPH05236042A (en) | 1993-09-10 |
| JP2874703B2 JP2874703B2 (en) | 1999-03-24 |
Family
ID=12347703
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4032038A Expired - Fee Related JP2874703B2 (en) | 1992-02-19 | 1992-02-19 | False synchronization prevention device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2874703B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999016223A1 (en) * | 1997-09-19 | 1999-04-01 | Matsushita Electric Industrial Co., Ltd. | Modulator/demodulator and modulation/demodulation method |
| EP1039707A4 (en) * | 1997-12-04 | 2005-09-28 | Kenwood Corp | Digital radio receiver |
-
1992
- 1992-02-19 JP JP4032038A patent/JP2874703B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999016223A1 (en) * | 1997-09-19 | 1999-04-01 | Matsushita Electric Industrial Co., Ltd. | Modulator/demodulator and modulation/demodulation method |
| CN100375475C (en) * | 1997-09-19 | 2008-03-12 | 松下电器产业株式会社 | Modulation, demodulation device and method |
| EP1039707A4 (en) * | 1997-12-04 | 2005-09-28 | Kenwood Corp | Digital radio receiver |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2874703B2 (en) | 1999-03-24 |
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