JPH04132316A - Low-pass filer changeover circuit - Google Patents
Low-pass filer changeover circuitInfo
- Publication number
- JPH04132316A JPH04132316A JP25324390A JP25324390A JPH04132316A JP H04132316 A JPH04132316 A JP H04132316A JP 25324390 A JP25324390 A JP 25324390A JP 25324390 A JP25324390 A JP 25324390A JP H04132316 A JPH04132316 A JP H04132316A
- Authority
- JP
- Japan
- Prior art keywords
- low
- pass filter
- switch
- circuit
- detection circuit
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 claims abstract description 31
- 230000001360 synchronised effect Effects 0.000 claims description 3
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 230000003321 amplification Effects 0.000 description 6
- 238000003199 nucleic acid amplification method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Landscapes
- Synchronizing For Television (AREA)
- Superheterodyne Receivers (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、テレビジョン受像機などが受信する高周波映
像信号に、残留位置変調(搬送波の位相が映像信号の振
幅で変化する)成分が含まれた場合に生じやすい同期乱
れを検出してテレビジョン受像機での同期乱れを最小限
にとどめるために、中間周波数検波用電圧制御発振器の
発振周波数を制御する位相制御回路に用いられるローパ
スフィルタを任意に切替えるようにしたローパスフィル
タ切替回路に関する。[Detailed Description of the Invention] Industrial Field of Application The present invention is applicable to high-frequency video signals received by television receivers, etc. that contain a residual position modulation component (the phase of the carrier wave changes with the amplitude of the video signal). In order to detect synchronization disturbances that tend to occur in some cases and minimize synchronization disturbances in television receivers, the low-pass filter used in the phase control circuit that controls the oscillation frequency of the voltage-controlled oscillator for intermediate frequency detection can be optionally used. The present invention relates to a low-pass filter switching circuit configured to switch.
従来の技術
従来のテレビジョン受像機においては、中間周波数検波
回路の検波手段として自ら発振器を有する回路では、位
相ロックのだめのローパスフィルタ切替えは、映像信号
のロック非ロック検出回路によシ受信電波の強弱に応じ
て周波数引込み範囲を切替えるという形で行なわれてい
る。BACKGROUND ART In conventional television receivers, in a circuit that has its own oscillator as a detection means for an intermediate frequency detection circuit, switching of a low-pass filter for phase locking is performed by a video signal lock/unlock detection circuit. This is done by switching the frequency pull-in range depending on the strength.
以下従来の構成について図面を参照しながら説明する。The conventional configuration will be described below with reference to the drawings.
第6図は、従来の中間周波数検波回路の構成を示すもの
であり、中間周波数増幅部51゜中間周波数検波回路6
2.電圧制御発振器63゜位相制御検波回路54.ロッ
ク時定数切替部(以下ローパスフィルタと記載)55.
ロック非ロック検出回路56で構成されている。以
上のように構成された回路について、以下その動作を説
明する。FIG. 6 shows the configuration of a conventional intermediate frequency detection circuit, in which the intermediate frequency amplification section 51° intermediate frequency detection circuit 6
2. Voltage controlled oscillator 63° phase controlled detection circuit 54. Lock time constant switching unit (hereinafter referred to as low-pass filter) 55.
It is composed of a lock/unlock detection circuit 56. The operation of the circuit configured as above will be described below.
中間周波映像信号は、中間周波数増幅部51で増幅され
たのち中間周波数検波回路52および位相制御検波回路
54に送られる。位相制御検波回路54は、電圧制御発
振器63より入力される周波数で、中間周波増幅部61
より入力される中間周波映像信号を位相検波したのち、
ローパスフィルタ66を通シこの信号によって電圧制御
発振器530位相を制御している。上記ローパスフィル
タ65は、受信電波の強弱に応じてロック非ロック検出
回路56によって制御され、受信電波の強い時はロック
非ロック検出回路56の出力は、接地されてローパスフ
ィルタ55の時定数は重くなりしたがって周波数引込み
範囲は狭くなる。逆に受信電波の弱い時は、ロック非ロ
ック検出回路66の出力は、開放されてローパスフィル
タの時定数は軽くなシしたがって周波数引込み範囲は広
くなる。従来は以上の回路構成による、いわゆる完全な
同期検波回路が使用されていた。The intermediate frequency video signal is amplified by an intermediate frequency amplification section 51 and then sent to an intermediate frequency detection circuit 52 and a phase control detection circuit 54. The phase control detection circuit 54 uses the frequency input from the voltage control oscillator 63 to generate an intermediate frequency amplification section 61.
After phase-detecting the intermediate frequency video signal input from
This signal passes through a low-pass filter 66 and controls the phase of the voltage controlled oscillator 530. The low-pass filter 65 is controlled by a lock/unlock detection circuit 56 depending on the strength of the received radio waves. When the received radio waves are strong, the output of the lock/unlock detection circuit 56 is grounded and the time constant of the low-pass filter 55 becomes heavy. Therefore, the frequency pull-in range becomes narrower. Conversely, when the received radio waves are weak, the output of the lock/unlock detection circuit 66 is open, and the time constant of the low-pass filter is light, so the frequency pull-in range becomes wide. Conventionally, a so-called complete synchronous detection circuit having the above circuit configuration has been used.
発明が解決しようとする課題
以上のように従来回路に使用されていたローパスフィル
タの時定数は、テレビジョン受像機への受信電波の強弱
のみを検出して切替え、テレビジョン受像機への残留位
相変調成分が含まれた強い電波を受信する場合には、ロ
ーパスフィルタの時定数は重いため入来電波への追従が
遅くなり、検波された映像信号の同期信号部分に歪を生
じ同期乱れを生じていた。Problems to be Solved by the Invention As mentioned above, the time constant of the low-pass filter used in conventional circuits detects only the strength and weakness of the received radio waves to the television receiver and switches, and the residual phase to the television receiver is When receiving strong radio waves containing modulated components, the time constant of the low-pass filter is heavy, making it slow to follow the incoming radio waves, causing distortion in the synchronization signal part of the detected video signal and causing synchronization disturbance. was.
近年ビデオテープレコーダやゲーム機器の普及に伴ない
、残留位相変調成分を含んだ電波(高周波信号)を発生
する機器が増加し、それをテレビジタン受像機に接続し
た場合同期乱れや同期流れを生じやすく使用者に不快感
を与えるとともにこれらの機器の使用ができない場合す
らあった。In recent years, with the spread of video tape recorders and game devices, the number of devices that generate radio waves (high frequency signals) containing residual phase modulation components has increased, and when these devices are connected to a television receiver, synchronization disturbances and synchronization errors may occur. This often caused discomfort to the users and even made it impossible to use these devices.
課題を解決するだめの手段
本発明は上記課題を解決するために、新しく任意ローパ
スフィルタ切替回路を設け、使用者が残留位相変調成分
を含んだ電波をテレビジョン受像機で受信する場合同期
乱れを防ぐようにしたものである。Means for Solving the Problems In order to solve the above problems, the present invention provides a new arbitrary low-pass filter switching circuit to prevent synchronization disturbance when a user receives radio waves containing residual phase modulation components with a television receiver. It was designed to prevent this.
作 用
本発明は上記した構成のように任意ローパスフィルタ切
替回路を設け、テレビジョン受像機で同期乱れを生じた
場合、ローパスフィルタの時定数を軽くして応答を速く
し同期乱れをなくしテレビジョン受像機使用者の不快感
を除くことができるようにしたもの・である。Function The present invention provides an arbitrary low-pass filter switching circuit as described above, and when a synchronization disturbance occurs in a television receiver, the time constant of the low-pass filter is lightened to speed up the response and eliminate the synchronization disturbance. It is designed to eliminate discomfort for the receiver user.
実施例
以下、本発明の一実施例について図面を参照しながら説
明する。第1図は本発明の一実施例における任意ローパ
スフィルタ切替回路の回路構成を示すものである。EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows the circuit configuration of an arbitrary low-pass filter switching circuit in one embodiment of the present invention.
第1図において従来使用されている(第5図で説明した
)O−パスフィルタ1,2,3.4に追加して、ローパ
スフィルタ用抵抗5.直流阻止用コンデンサ6.8.ダ
イオード7を導通するための直流用抵抗9.スイッチン
グ用トランジスタ10゜電流制御用抵抗11.12およ
びスイッチング13が新しく設けられている。以上のよ
うに構成された回路について以下その動作を説明する。In addition to the conventionally used O-pass filters 1, 2, 3.4 in FIG. 1 (described in FIG. 5), a low-pass filter resistor 5. DC blocking capacitor 6.8. DC resistor 9 for making diode 7 conductive. A switching transistor 10°, a current control resistor 11, 12, and a switching 13 are newly provided. The operation of the circuit configured as above will be explained below.
中間周波映像信号は中間周波数増幅部14で増幅された
のち位相制御検波回路16に送られる。上記位相制御検
波回路16は、電圧制御発振器16より入力される発振
周波数で前記中間周波数増幅部14より入力された中間
周波数を位相検波してえた出力はローパスフィルタ18
を通して電圧制御発振器16へ送られる。通常の動作で
は、スイッチ13は、接地側に接続されていてトランジ
スタ10は動作を停止し、ダイオード7から抵抗9に電
流が流れ抵抗5は交流的に短絡状態となり第6図で示さ
れた従来のローパスフィルタと同様の動作を行なう。The intermediate frequency video signal is amplified by the intermediate frequency amplification section 14 and then sent to the phase control detection circuit 16. The phase control detection circuit 16 phase-detects the intermediate frequency input from the intermediate frequency amplification section 14 using the oscillation frequency input from the voltage control oscillator 16, and outputs the output to a low-pass filter 18.
is sent to the voltage controlled oscillator 16 through. In normal operation, the switch 13 is connected to the ground side, the transistor 10 stops operating, and current flows from the diode 7 to the resistor 9, causing the resistor 5 to be in an alternating current short-circuited state. It operates in the same way as a low-pass filter.
つぎに、スイッチ13を電源側に接続するとトランジス
タ1oは動作状態となり、ダイオード7は、動作を停止
し抵抗5は、ローパスフィルタに直列にはいることにな
る。つまり、ロック非ロック検出回路17がロック状態
にあり、その出力が短絡であっても、スイッチ13を電
源に接続することにより、任意にローパスフィルタの時
定数を軽くすること(等飾帯域幅を変化)ができる。し
たがって残留位相変調成分を含んだ強い電波を受信した
ときスイッチ13を電源側に接続することにより、その
時定数を軽くして入来電波への追従を速くし同期乱れを
防ぐことができるものである。Next, when the switch 13 is connected to the power supply side, the transistor 1o becomes active, the diode 7 stops operating, and the resistor 5 is placed in series with the low-pass filter. In other words, even if the lock/unlock detection circuit 17 is in the locked state and its output is short-circuited, the time constant of the low-pass filter can be arbitrarily lightened (the equated bandwidth can be reduced by connecting the switch 13 to the power supply). change) is possible. Therefore, by connecting the switch 13 to the power supply side when a strong radio wave containing a residual phase modulation component is received, it is possible to reduce the time constant, speed up tracking of the incoming radio wave, and prevent synchronization disturbance. .
なお、本実施例ではローパスフィルタ18の時定数切替
をスイッチ13で行なったが、同期乱れを検出するため
に第2図のごとく水平偏向回路からの水平パルスと同期
信号を利用した同期検出回路3oを用いて同期乱れを自
動検出しその出力を第1図に示した抵抗12に接続して
もよい。In this embodiment, the time constant of the low-pass filter 18 is switched by the switch 13, but in order to detect synchronization disturbance, a synchronization detection circuit 3o using horizontal pulses and synchronization signals from the horizontal deflection circuit is used as shown in FIG. It is also possible to automatically detect synchronization disturbances using a synchronous circuit and connect its output to the resistor 12 shown in FIG.
また、ローパスフィルタの時定数切替のために第3図の
ようにテレビジョンチャンネル毎に使用者があらかじめ
記憶集積回路(たとえばメモリーIC)33にユーザコ
ントロールスイッチ31によシ記憶させておきスイッチ
データを自動的にマイクロコンピュータ32より出力さ
せてもよい。In addition, in order to switch the time constant of the low-pass filter, the user stores switch data in advance in the memory integrated circuit (for example, memory IC) 33 by the user control switch 31 for each television channel as shown in FIG. It may also be automatically output from the microcomputer 32.
さらに第4図のようにローパスフィルタ時定数切替のた
めに同期信号と水平パルスを利用した同期検出回路44
の出力をマイクロコンピュータ42にデータ入力として
加え上記ユーザコントロールスイッチ41によシ記憶さ
せた記憶用集積回路43の出力も同様にマイクロコンピ
ュータ42にデータ入力して、両者の出力をマイクロコ
ンピュータ42より出力させてもよい。Furthermore, as shown in FIG. 4, a synchronization detection circuit 44 that uses synchronization signals and horizontal pulses to switch the low-pass filter time constant.
In addition, the output of the storage integrated circuit 43 stored by the user control switch 41 is also input to the microcomputer 42 as data input, and both outputs are output from the microcomputer 42. You may let them.
発明の効果
以上のように本発明は、テレビジョン受像機で残留位相
変調成分を含んだ強い電波を受信しても、任意に位相制
御検波部(PLL )のローパスフィルタの時定数を速
くして同期乱れを防ぎ良好な画像を得ることができる。Effects of the Invention As described above, the present invention can arbitrarily increase the time constant of the low-pass filter of the phase control detection section (PLL) even when a television receiver receives strong radio waves containing residual phase modulation components. It is possible to prevent synchronization disturbance and obtain good images.
第1図は本発明の一実施例におけるローパスフィルタ切
替回路を示す回路図、第2図、第3図。
第4図は請求項2,3.4に記載された同期乱れ検出用
回路図、第6図は従来のローパスフィルタの回路図であ
る。
10・・・・・・スイッチングトランジスタ、13・・
・・・・スイッチ、14・・・・・・中間周波数増幅部
、16・・・・・・位相制御検波回路、16・・・・・
・電圧制御発振器、17・・・・・・ロック非ロック検
出回路、18・・・・・・ローパスフィルタ、30,4
4・・・・・・同期検出回路、33゜43・・・・・・
記憶用集積回路(メモリー I C)、32゜42・・
・・・・マイクロコンピュータ。
代理人の氏名 弁理士 小鍜治 明 ほか2名第2図
闇111乱l#1轄出口路
〃
コーザフ〉トロールスイッチ
マイク0フ+/げコータFIG. 1 is a circuit diagram showing a low-pass filter switching circuit in an embodiment of the present invention, and FIGS. 2 and 3. FIG. 4 is a circuit diagram for detecting synchronization disturbance according to claims 2 and 3.4, and FIG. 6 is a circuit diagram of a conventional low-pass filter. 10... Switching transistor, 13...
... Switch, 14 ... Intermediate frequency amplification section, 16 ... Phase control detection circuit, 16 ...
・Voltage controlled oscillator, 17... Lock/unlock detection circuit, 18... Low pass filter, 30, 4
4...Synchronization detection circuit, 33°43...
Memory integrated circuit (memory IC), 32°42...
...Microcomputer. Name of agent: Patent attorney Akira Okaji and 2 others Figure 2 Darkness 111 Ran #1 Jurisdiction Exit Route Kozaf Troll Switch Mic 0F+/Gekota
Claims (4)
御検波回路、ロック非ロック検出回路とを有する完全な
同期検波回路による中間周波数を検波する手段と上記電
圧制御発振器を制御する位相制御検波回路のローパスフ
ィルタの時定数を、スイッチで任意に切替えるようにし
たローパスフィルタ切替回路。(1) Means for detecting an intermediate frequency using a complete synchronous detection circuit including a voltage controlled oscillator operating at an intermediate frequency, a phase controlled detection circuit, and a lock/unlock detection circuit, and a phase controlled detection circuit that controls the voltage controlled oscillator. A low-pass filter switching circuit in which the time constant of the low-pass filter can be arbitrarily changed using a switch.
ルスを利用した同期検出回路よりなる特許請求の範囲第
1項記載のローパスフィルタ切替回路。(2) The low-pass filter switching circuit according to claim 1, wherein the switch circuit according to claim 1 comprises a synchronization detection circuit using a synchronization signal and a horizontal pulse.
に記憶されたマイクロコンピュータ出力よりなる特許請
求の範囲第1項記載のローパスフィルタ切替回路。(3) The low-pass filter switching circuit according to claim 1, wherein the switch circuit according to claim 1 comprises a microcomputer output stored in a storage integrated circuit.
パルスを利用した同期検出回路と記憶用集積回路に記憶
されたマイクロコンピュータ出力よりなる特許請求の範
囲第1項記載のローパスフィルタ切替回路。(4) The low-pass filter switching circuit according to claim 1, wherein the switch circuit according to claim 1 comprises a synchronization detection circuit using a synchronization signal and a horizontal pulse, and a microcomputer output stored in a storage integrated circuit. .
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2253243A JP2727749B2 (en) | 1990-09-21 | 1990-09-21 | Low-pass filter switching circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2253243A JP2727749B2 (en) | 1990-09-21 | 1990-09-21 | Low-pass filter switching circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH04132316A true JPH04132316A (en) | 1992-05-06 |
JP2727749B2 JP2727749B2 (en) | 1998-03-18 |
Family
ID=17248553
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2253243A Expired - Fee Related JP2727749B2 (en) | 1990-09-21 | 1990-09-21 | Low-pass filter switching circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2727749B2 (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5946043U (en) * | 1982-09-17 | 1984-03-27 | ソニー株式会社 | radio receiver |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5946043B2 (en) * | 1978-08-16 | 1984-11-10 | 株式会社日立製作所 | magnetic recording and reproducing device |
-
1990
- 1990-09-21 JP JP2253243A patent/JP2727749B2/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5946043U (en) * | 1982-09-17 | 1984-03-27 | ソニー株式会社 | radio receiver |
Also Published As
Publication number | Publication date |
---|---|
JP2727749B2 (en) | 1998-03-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JPH07154287A (en) | Direct conversion receiver | |
JPH06343166A (en) | High frequency receiver | |
US6169458B1 (en) | Differential charge pump with reduced charge-coupling effects | |
EP0582390B1 (en) | Dual mode phase-locked loop | |
US4443769A (en) | Frequency search system for a phase locked loop | |
US6133802A (en) | Synchronous carrier recovery circuit and injection locked oscillator | |
US4940951A (en) | Phase lock recovery apparatus for phase locked loop circuit | |
US6047170A (en) | Automatic squelch control for narrow band AM radio | |
JPH04132316A (en) | Low-pass filer changeover circuit | |
US6008693A (en) | FM-sound demodulator for TV sound signals and method of detecting sound carriers | |
US5049838A (en) | Minimum intrusion search oscillator for use in feedback loops | |
JP2877834B2 (en) | Variable frequency oscillator synchronization circuit | |
CA2212774C (en) | Circuit for causing fpll to lock in desired phase | |
JPS644386B2 (en) | ||
JP2693775B2 (en) | Video receiving circuit | |
JPS63236405A (en) | Fm receiver | |
JPH06103827B2 (en) | Automatic frequency control circuit | |
JPH06237272A (en) | Receiver | |
JP2904105B2 (en) | Doppler frequency tracker | |
JPH04189034A (en) | Phase locked loop pick-up circuit in common use with afc loop | |
JPS5925986B2 (en) | direction finder | |
JPS58207773A (en) | Phase locking device | |
JP2894112B2 (en) | Phase synchronous receiving circuit | |
JPS62241407A (en) | Fm receiver | |
JPH0314373A (en) | Video intermediate frequency signal processor |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20071212 Year of fee payment: 10 |
|
FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081212 Year of fee payment: 11 |
|
LAPS | Cancellation because of no payment of annual fees |