JPS5950145B2 - FM stereo receiver pilot signal removal device - Google Patents
FM stereo receiver pilot signal removal deviceInfo
- Publication number
- JPS5950145B2 JPS5950145B2 JP2027578A JP2027578A JPS5950145B2 JP S5950145 B2 JPS5950145 B2 JP S5950145B2 JP 2027578 A JP2027578 A JP 2027578A JP 2027578 A JP2027578 A JP 2027578A JP S5950145 B2 JPS5950145 B2 JP S5950145B2
- Authority
- JP
- Japan
- Prior art keywords
- pilot signal
- circuit
- signal
- output
- mixer
- 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
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H40/00—Arrangements specially adapted for receiving broadcast information
- H04H40/18—Arrangements characterised by circuits or components specially adapted for receiving
- H04H40/27—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
- H04H40/36—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving
- H04H40/45—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving
- H04H40/72—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving for noise suppression
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/1646—Circuits adapted for the reception of stereophonic signals
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Noise Elimination (AREA)
- Stereo-Broadcasting Methods (AREA)
Description
【発明の詳細な説明】
この発明は特にＦＭステレオ受信機に係り、特にそのパ
イロット信号除去装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to an FM stereo receiver, and more particularly to a pilot signal removal device thereof.
周知のようにＦＭステレオ放送においては、受信機側で
ステレオ信号を復調するのに必要な信号としていわゆる
パイロット信号（１９ｋＨｚ）を使用している。As is well known, in FM stereo broadcasting, a so-called pilot signal (19 kHz) is used as a signal necessary for demodulating a stereo signal on the receiver side.
従って、このパイロット信号は復調用に供された後はメ
イン信号から除去される必要がある。Therefore, this pilot signal needs to be removed from the main signal after being used for demodulation.
このため、従来より位相同期ループ（ＰＬＬ）回路を用
いる如くした種々のパイロットキャンセラー回路が考案
されているが、その殆んどが初めにキャンセル量をボリ
ューム等で調整すれば後は入力レベルに追従してキャン
セル動作を行なう如くしたいわゆる半自動形のものであ
るために、初めの調整作業が煩雑となる欠点を有してい
た。For this reason, various pilot canceller circuits that use phase-locked loop (PLL) circuits have been devised in the past, but most of them are designed to first adjust the amount of cancellation using a volume, etc., and then follow the input level. Since it is of a so-called semi-automatic type in which a canceling operation is performed, it has the disadvantage that the initial adjustment work is complicated.
而して、全自動的にパイロット信号を除去するには閉回
路を構成して一部に負帰還をかけることにより、パイロ
ット信号に対して逆相のキャンセル信号を注入してパイ
ロット信号を除去することが考えられる。Therefore, in order to completely automatically remove the pilot signal, by constructing a closed circuit and applying negative feedback to a part of the circuit, a cancellation signal of the opposite phase to the pilot signal is injected to remove the pilot signal. It is possible that
しかしながら、この場合使用する回路素子のばらつきや
非直線性により誤差が生じるとパイロット信号が入力さ
れないときに出力端からキャンセル信号が導出されてし
まうような欠点を有していた。However, in this case, if an error occurs due to variations or nonlinearity of the circuit elements used, there is a drawback that a cancellation signal is derived from the output terminal when no pilot signal is input.
そこで、この発明は以上のような点に鑑みてなされたも
ので、負帰還ループ中にパイロット信号のレベルに応じ
て該負帰還ループを断接せしめるヒステリシス回路を挿
入することにより、パイロット信号がない場合にキャン
セル信号が導出されることなくしかも全自動的に良好に
パイロット信号を除去し得るようにした極めて優れたＦ
Ｍステレオ受信機の信号除去装置を提供することを目的
としている。Therefore, the present invention has been made in view of the above points, and by inserting a hysteresis circuit in the negative feedback loop that connects and disconnects the negative feedback loop according to the level of the pilot signal, it is possible to eliminate the absence of a pilot signal. An extremely excellent F that can effectively eliminate the pilot signal without any cancellation signal being derived in the case of
The present invention aims to provide a signal cancellation device for an M stereo receiver.
以下図面を参照してこの発明の一実施例につき詳細に説
明する。An embodiment of the present invention will be described in detail below with reference to the drawings.
すなわち、図においてＩＮはＦＭステレオ受信機の復調
回路等でなる信号源Ｖｇから周波数ｆ１なるメイン信号
■ｆ１および周波数ｆ。That is, in the figure, IN is a main signal f1 having a frequency f1 and a main signal f1 having a frequency f1 from a signal source Vg such as a demodulation circuit of an FM stereo receiver.
（＝ １９ｋ）ｉｉｓ）なるパイロット信号■ｆｏとの
合成信号ＶＩＮが供給される入力端である。This is an input terminal to which a composite signal VIN with a pilot signal fo (= 19k)iis) is supplied.
この入力端ＩＮはバッファ回路１１およびＰＬＬ回路１
２の入力端に接続される。This input terminal IN is connected to the buffer circuit 11 and the PLL circuit 1.
Connected to the input terminal of 2.
そして、前記バッファ回路１１の出力端は混合器１３の
入力側一端に接続され、前記ＰＬＬ回路１２の出力端は
後述する閉ループＬを構成する同期検波器１４および電
圧制御増幅器１５の各入力側一端に接続される。The output end of the buffer circuit 11 is connected to one end of the input side of a mixer 13, and the output end of the PLL circuit 12 is connected to one end of the input side of a synchronous detector 14 and a voltage control amplifier 15, which constitute a closed loop L to be described later. connected to.
また、前記電圧制御増幅器１５はその入力側他端が前記
同期検波器１４の出力端にヒステリシス回路１６を介し
て接続され且つその出力端が前記混合器１３の入力側他
端に接続される。Further, the other input end of the voltage control amplifier 15 is connected to the output end of the synchronous detector 14 via a hysteresis circuit 16, and the output end thereof is connected to the other input end of the mixer 13.
さらに、前記混合器１３の出力端は増幅器１７を介して
出力端０！ＪＴに接続されると共に、増幅器１８を介し
て前記同期検波器１４０入力側他端に接続される。Further, the output terminal of the mixer 13 is connected to the output terminal 0! via the amplifier 17. JT, and is also connected via an amplifier 18 to the other input end of the synchronous detector 140.
二三で、前記ＰＬＬ回路１２は周知の位相同期ルーを回
路であって、この場合その自走周波数を前記パイロット
信号Ｖｆｏの周波数ｆ。The PLL circuit 12 is a well-known phase-locked loop circuit, and in this case, its free running frequency is the frequency f of the pilot signal Vfo.
近く設定しておくことによって、パイロット信号ｖｆｏ
が入ると周波数ｆ。By setting it close to the pilot signal vfo
When , the frequency f.
に同期した信号を導出するものである。また、前記閉ル
ープＬは前記したように増幅器１８、同期検波器１４、
ヒステリシス回路１６および電圧制御増幅器１５をルー
プ状に構成したもので、この場合後述する作用により電
圧制御増幅器１５から得られるパイロット信号の逆相成
分−Ｖｆｏで負帰還がかけられるようになされている。This method derives a signal synchronized with the . Further, as described above, the closed loop L includes the amplifier 18, the synchronous detector 14,
The hysteresis circuit 16 and the voltage control amplifier 15 are configured in a loop, and in this case, negative feedback is applied by the negative phase component -Vfo of the pilot signal obtained from the voltage control amplifier 15 by the action described later.
そして、該閉ループＬ中に介挿されたヒステリシス回路
１６は同期検波器１４から検出されるパイロット信号Ｖ
ｆｏのレベルに応じてオンまたはオフ状態をとるスイッ
チング回路で構成されるが、オン・オフのレベルが互い
に異なる如くしたいわゆるヒステリシス機能を併持させ
たものであり、そのオン・オフのレベルは装置を安定に
動作させるためにＶｆｏ−ＯＮ＞Ｖｆｏ−ＯＦＦの如く
装置の安定性の状態により最適値に設定される。The hysteresis circuit 16 inserted in the closed loop L is connected to the pilot signal V detected from the synchronous detector 14.
It is composed of a switching circuit that takes an on or off state depending on the level of fo, but it also has a so-called hysteresis function that makes the on and off levels different from each other, and the on and off levels are determined by the device. In order to operate stably, the optimum value is set depending on the stability state of the device, such as Vfo-ON>Vfo-OFF.
而して、以上の構成において信号源Ｖｇがらメイン信号
Ｖｆ１とパイロット信号Ｖｆｏとの合成信号ＶＩＮが供
給されたとすると、ＰＬＬ回路１２からは前記したよう
にパイロット信号ｖｆｏの周波数ｆ。In the above configuration, if the signal source Vg supplies the composite signal VIN of the main signal Vf1 and the pilot signal Vfo, the PLL circuit 12 outputs the frequency f of the pilot signal vfo as described above.
に同期した信号が導出されると共に、バッファ回路１１
を介して合成信号ＶＩＮがそのまま混合器１３の入力側
一端に導出される。A signal synchronized with the buffer circuit 11 is derived.
The composite signal VIN is directly delivered to one input side of the mixer 13 via the mixer 13.
この合成信号ＶＩＮは増幅器１８を介して同期検波器１
４に供給され、ここで前記ＰＬＬ回路１２からのパイロ
ット信号Ｖｆｏに同期した信号により同期検波されるこ
とにより、パイロット信号ｖｆｏ成分のみが検出されて
ヒステリシス回路１６に加えられる。This composite signal VIN is sent to the synchronous detector 1 via the amplifier 18.
4, and is subjected to synchronous detection using a signal synchronized with the pilot signal Vfo from the PLL circuit 12, whereby only the pilot signal vfo component is detected and added to the hysteresis circuit 16.
そして、ヒステリシス回路１６は加えられるパイロット
信号ｖｆｏ成分をレベル弁別し、前記Ｖｆｏ−ＯＦＦよ
りも低い場合にはオフ状態をとる。Then, the hysteresis circuit 16 discriminates the level of the added pilot signal vfo component, and assumes an OFF state if it is lower than the Vfo-OFF.
これによって同期検波回路１４と電圧制御増幅器１５と
が切離されるために、閉ループＬが断路されるので電圧
制御増幅器１５からはキャンセル信号となるパイロット
信号の逆相成分が導出されない。As a result, the synchronous detection circuit 14 and the voltage control amplifier 15 are separated, and the closed loop L is disconnected, so that the voltage control amplifier 15 does not derive the negative phase component of the pilot signal that becomes the cancellation signal.
すなわち、こ、の状態では増幅器１７を介して出力端に
合成信号ＶＩＮが導出される。That is, in this state, the composite signal VIN is derived to the output terminal via the amplifier 17.
但し、この合成信号に含まれるパイロット信号ｖｆｏ成
分は所定レベル以下の小量である。However, the pilot signal vfo component included in this composite signal is a small amount below a predetermined level.
一方ヒステリシス回路１６に加えられるパイロット信号
ｖｆｏ成分が前記Ｖｆｏ−ＯＮなるレベルを越えると、
ヒステリシス回路１６がオン状態となるので同期検波回
路１４と電圧制御増幅器１５とが接続される。On the other hand, when the pilot signal vfo component applied to the hysteresis circuit 16 exceeds the level of Vfo-ON,
Since the hysteresis circuit 16 is turned on, the synchronous detection circuit 14 and the voltage control amplifier 15 are connected.
これによって閉ループＬが液路されるので電圧制御増幅
器１５からはキャンセル信号となるパイロット信号の逆
相成分−Ｖｆｏが混合器１３の他方の入力側に負帰還さ
れるようになる。As a result, the closed loop L is closed, so that the negative phase component -Vfo of the pilot signal, which serves as a cancellation signal, is negatively fed back from the voltage control amplifier 15 to the other input side of the mixer 13.
すなわち、この状態では合成信号ＶＩＮ中のパイロット
信号Ｖｆｏがキャンセル信号−Ｖｆｏによってキャンセ
ルされるので、増幅器１７を介して出力端ＯＵＴからメ
イン信号Ｖｆ１成分のみが導出される。That is, in this state, the pilot signal Vfo in the composite signal VIN is canceled by the cancellation signal -Vfo, so only the main signal Vf1 component is derived from the output terminal OUT via the amplifier 17.
この場合、パイロット信号Ｖｆｏの残留量は増幅器１８
、同期検波回路１４および電圧制御増幅器１５のオープ
ンループゲインに逆比例して少なくなり、実質的にキャ
ンセルされたのと等価である。In this case, the residual amount of pilot signal Vfo is
, decreases in inverse proportion to the open loop gains of the synchronous detection circuit 14 and the voltage control amplifier 15, and is equivalent to being substantially canceled.
なお、この場合、電圧制御増幅器１５は前記ＰＬＬ回路
１２から導出されるパイロット信号Ｖｆ。In this case, the voltage control amplifier 15 receives the pilot signal Vf derived from the PLL circuit 12.
に同期した信号が位相基準信号として入力されると共に
、ヒステリシス回路１６からの出力レベルによって制御
されそれがオンレベルのとき、前記パイロット信号ｖｆ
ｏと逆相関係にあるキャンセル信号−Ｖｆｏを出力する
。A signal synchronized with the pilot signal vf is input as a phase reference signal, and is controlled by the output level from the hysteresis circuit 16, and when it is on level, the pilot signal vf
A cancel signal -Vfo having a negative phase relationship with o is output.
ところで、上記の閉ループＬ中にヒステリシス回路１６
が介挿されないとすると常に負帰還ループが形成されて
いるので、増幅器１８、同期検波回路１４および電圧制
御増幅器１５に使用する回路素子のばらつきや非直線性
による誤差が生じ、入力合成信号ＶＩＮ中にパイロット
信号ｖｆｏ成分がないときでも、キャンセル信号が作ら
れて出力端ＯＵＴに導出されるようになって安定性が損
なわれるようになるから、上述したようにこの発明によ
ればかかる欠点を除去し得るという有用性をもっている
もので゛あることが明白で゛ある。By the way, the hysteresis circuit 16 is included in the closed loop L mentioned above.
If VIN is not inserted, a negative feedback loop is always formed, which causes errors due to variations and nonlinearity of the circuit elements used in the amplifier 18, synchronous detection circuit 14, and voltage control amplifier 15, and Even when there is no pilot signal vfo component, a cancellation signal is generated and guided to the output terminal OUT, resulting in loss of stability. According to the present invention, as described above, this drawback is eliminated. It is clear that there are some useful things that can be done.
従って、以上詳述したようにこの発明によれば負帰還ル
ーフ沖にパイロット信号のレベルに応じて該負帰還ルー
プを断接せしめるヒステリシス回路を挿入することによ
り、パイロット信号がない場合にキャンセル信号が導出
されることなくしかも全自動的に良好に不要信号を除去
し得る極めて優れたＦＭステレオ受信機のパイロット信
号除去装置を提供することが可能となる。Therefore, as detailed above, according to the present invention, by inserting a hysteresis circuit in the negative feedback roof that connects and disconnects the negative feedback loop according to the level of the pilot signal, a cancellation signal is generated when there is no pilot signal. It becomes possible to provide an extremely excellent pilot signal removal device for an FM stereo receiver that can fully automatically remove unnecessary signals without being derived.
図はこの発明に係るＦＭステレオ受信機のパイロット信
号除去装置の一実施例を示す回路構成図である。
ＩＮ・・・・・・入力端、Ｖｇ・・・・・・信号源、１
１・・・・・・バッファ回路、１２・・・・・・ＰＬＬ
回路、１３・・・・・・混合器、１４・・・・・・同期
検波器、１５・・・・・・電圧制御増幅器、１６・・・
・・・ヒステリシス回路、１７，１８・・・・・・増幅
器、Ｌ・・・・・・閉ループ、ＯＵＴ・・・・・・出力
端。FIG. 1 is a circuit configuration diagram showing an embodiment of a pilot signal removal device for an FM stereo receiver according to the present invention. IN...Input terminal, Vg...Signal source, 1
1...Buffer circuit, 12...PLL
Circuit, 13... Mixer, 14... Synchronous detector, 15... Voltage control amplifier, 16...
...Hysteresis circuit, 17, 18...Amplifier, L...Closed loop, OUT...Output terminal.
Claims (1)
に位相同期する位相同期ループ回路と、前記合成信号が
入力一端に加えられる混合器と、この混合器からの出力
を前記位相同期ループ回路からの出力により同期検波し
てパイロット信号成分を導出する同期検波回路と、この
同期検波回路からのパイロット信号成分をレベル弁別し
てそれが第１の所定レベルよりも低い状態でオフ出力を
且つ第２の所定レベルよりも高い状態でオン出力を与え
るヒステリシス回路と、このヒステリシス回路からの出
力により制御されそれがオン出力のとき前記パイロット
信号と逆相関係にあるキャンセル信号を前記混合器の入
力他端に供給する電圧制御増幅器と、前記混合器からの
出力を導出する出力回路とを具備してなることを特徴と
するＦＭステレオ受信機のパイロット信号除去装置。A phase-locked loop circuit that is phase-locked to the pilot signal component in the I FM stereo composite signal, a mixer to which the composite signal is added to one input end, and an output from the mixer that is synchronized with the output from the phase-locked loop circuit A synchronous detection circuit that derives a pilot signal component by synchronous detection; and a synchronous detection circuit that discriminates the level of the pilot signal component from this synchronous detection circuit and outputs an OFF output when the pilot signal component is lower than a first predetermined level and is lower than a second predetermined level. a hysteresis circuit that provides an on output when the pilot signal is high; and a voltage that is controlled by the output from this hysteresis circuit and supplies a cancellation signal that is in a negative phase relationship with the pilot signal to the other end of the input of the mixer when the hysteresis circuit is on output. A pilot signal removal device for an FM stereo receiver, comprising a control amplifier and an output circuit for deriving an output from the mixer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2027578A JPS5950145B2 (en) | 1978-02-23 | 1978-02-23 | FM stereo receiver pilot signal removal device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2027578A JPS5950145B2 (en) | 1978-02-23 | 1978-02-23 | FM stereo receiver pilot signal removal device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS54112102A JPS54112102A (en) | 1979-09-01 |
| JPS5950145B2 true JPS5950145B2 (en) | 1984-12-06 |
Family
ID=12022613
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2027578A Expired JPS5950145B2 (en) | 1978-02-23 | 1978-02-23 | FM stereo receiver pilot signal removal device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5950145B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6093839A (en) * | 1983-10-26 | 1985-05-25 | Akai Electric Co Ltd | Information transmission system using dither |
| EP1630713B1 (en) * | 2004-08-24 | 2020-05-20 | Sony Deutschland GmbH | Backscatter interrogator reception method and interrogator for a modulated backscatter system |
-
1978
- 1978-02-23 JP JP2027578A patent/JPS5950145B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS54112102A (en) | 1979-09-01 |
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