JPS63179672A - Detection circuit - Google Patents
Detection circuitInfo
- Publication number
- JPS63179672A JPS63179672A JP62010722A JP1072287A JPS63179672A JP S63179672 A JPS63179672 A JP S63179672A JP 62010722 A JP62010722 A JP 62010722A JP 1072287 A JP1072287 A JP 1072287A JP S63179672 A JPS63179672 A JP S63179672A
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- Prior art keywords
- signal
- video
- circuit
- filter
- output
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Links
- 238000001514 detection method Methods 0.000 title claims abstract description 31
- 239000000284 extract Substances 0.000 claims description 2
- 230000005236 sound signal Effects 0.000 abstract description 10
- 230000006866 deterioration Effects 0.000 abstract 1
- 230000010363 phase shift Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 5
- 230000001360 synchronised effect Effects 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000010897 surface acoustic wave method Methods 0.000 description 1
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- Television Receiver Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
（イ）産業上の利用分野
本発明は、テレビジョン受像機に用いられる検波回路に
関するもので、特にＩＣ（集積回路）化に適した検波回
路に関する。DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a detection circuit used in a television receiver, and particularly to a detection circuit suitable for integration into an IC (integrated circuit).
（ロ）従来の技術
テレビジョン受像機においては、映像搬送波と音声搬送
波の周波数差に相当する４ 、 ５ ＭＨｚのビート成
分を取り出して、これをＦＭ検波することによって音声
信号を得ている。前記４ 、５ ＭＨｚのビート成分の
取り出し方には映像検波回路を兼用して取り出す方法と
、映像検波回路とは別に独立した検波回路を用いる方法
とがある。その様な、検波方法は例えば昭和６０年５月
１日付で日本放送出版協会から発行された’ＮＨＫカラ
ーテレビ教科＠（上）」第２７９頁に記載されている。(b) Conventional technology In a television receiver, an audio signal is obtained by extracting a beat component of 4 or 5 MHz, which corresponds to the frequency difference between a video carrier wave and an audio carrier wave, and subjecting it to FM detection. There are two methods for extracting the beat components of 4 and 5 MHz: one is to use a video detection circuit as well, and the other is to use an independent detection circuit separate from the video detection circuit. Such a detection method is described, for example, on page 279 of ``NHK Color Television Education Course @ (Part 1)'' published by the Japan Broadcasting Publishing Association on May 1, 1985.
又、チューナの出力信号を映像信号と音声信号とに分離
してから検波する方法も提案されている。第２図はその
様な検波方法を示す回路図で、チューナ（１）からの映
像ＩＦ（中間周波）信号は第１ＳＡＷ（表面弾性波フィ
ルタ）フィルタ（２）を通過した後、映像ＩＦ増幅器（
３）で増幅される。位相比較器（４）、ローパスフィル
タ（５）及びＶＣＯ（７ｔｔ圧制御発振器）（６）から
なるＰＬＬ回路（Ｚ）は、前記映像ＩＦ増幅器（３）か
らの映像ＩＦ信号にロックする。映像検波器（８〉は映
像ＩＦ増幅器（３〉の出力映像ＩＦ信号をＰＬＬ回路（
７）の出力信号により同期検波する。その為、映像信号
が出力端子（９）に発生ずる。A method has also been proposed in which the tuner output signal is separated into a video signal and an audio signal and then detected. Figure 2 is a circuit diagram showing such a detection method, in which the video IF (intermediate frequency) signal from the tuner (1) passes through the first SAW (surface acoustic wave filter) filter (2), and then passes through the video IF amplifier (
3) is amplified. A PLL circuit (Z) consisting of a phase comparator (4), a low-pass filter (5) and a VCO (7tt pressure controlled oscillator) (6) locks to the video IF signal from the video IF amplifier (3). The video detector (8>) converts the output video IF signal of the video IF amplifier (3>) into the PLL circuit (
7) Performs synchronous detection using the output signal. Therefore, a video signal is generated at the output terminal (9).
一方、チューナ（１）からの音声ＩＦ信号は、第２５Ａ
Ｗフィルタ（１０）を通過し、音声ＩＦ増幅器（１１）
で増幅され乗算回路（１２）に印加される。乗算回路（
１２）にはＶ ＣＯ（６）の出力信号が印加されている
ので両信号の乗算が行なわれ４゜５ ＭＨｚのビート成
分が出力端子（１３）に発生ずる。On the other hand, the audio IF signal from tuner (1) is
Passes through W filter (10) and audio IF amplifier (11)
The signal is amplified and applied to the multiplication circuit (12). Multiplication circuit (
Since the output signal of the VCO (6) is applied to the output terminal (12), both signals are multiplied and a beat component of 4.5 MHz is generated at the output terminal (13).
従って、第２図の回路によれば単一のｖＣｏを用いて映
像信号を検波できるとともに４ 、５ ＭＨｚのビート
成分を得ることが出来る。Therefore, according to the circuit shown in FIG. 2, a video signal can be detected using a single vCo, and a beat component of 4 or 5 MHz can be obtained.
（ハ）発明が解決しようとする問題点
しかしながら、第２図の回路においてはテレビ信号の伝
送方式が残留側波帯方式であることから、検波回路にお
ける高域強調を防止する為第３図（イ）の如く映像搬送
波周波数が第１ＳＡＷフィルタ（２）の減衰域に位置す
る様に、前記第１ＳＡＷフィルタ（２）のフィルタ特性
を定める必要がある。しかしながら、そうすると映像搬
送波の上下側帯波間に不平衡が生じフィルタ通過後の映
像ＩＦ信号は位相変調を受けＰＬＬ回路（Ｚ）は前記位
相変調を受けた映像ＩＦ信号に同期してしまう。(c) Problems to be Solved by the Invention However, since the TV signal transmission method in the circuit shown in FIG. 2 is a vestigial sideband method, the circuit shown in FIG. It is necessary to determine the filter characteristics of the first SAW filter (2) so that the video carrier frequency is located in the attenuation range of the first SAW filter (2) as shown in (b). However, in this case, an imbalance occurs between the upper and lower sidebands of the video carrier wave, and the video IF signal after passing through the filter is subjected to phase modulation, and the PLL circuit (Z) becomes synchronized with the video IF signal that has undergone the phase modulation.
すると、Ｖ ＣＯ（６）から位相変調を受けた映像ＩＦ
信号に同期した出力信号が乗算回路（１２）に印加され
るようになり、乗算回路（１２）において正しい４ 、
５ Ｍ）ｌｚのビート成分が取り出せなくなり音質が劣
化してしまうという問題があった。Then, the video IF that received phase modulation from V CO (6)
An output signal synchronized with the signal is now applied to the multiplier circuit (12), and the correct 4,
There was a problem that the beat component of 5M)lz could not be extracted and the sound quality deteriorated.
尚、前記現象は、昭和４７年６月１日付でテレビジョン
学会より発行された雑誌１テレビジョンＪＶＯＬ、 ２
６ Ｎｏ、 ６第４６４頁に詳細に記述されている。The above phenomenon is described in the magazines 1 Television JVOL, 2 published by the Television Society on June 1, 1971.
6 No. 6, page 464.
（ニ）問題点を解決するための手段
本発明は、上述の点に鑑み成されたもので映像ＩＦ信号
を通過きせる第１フィルタと、映像ＩＦ信号及び音声Ｉ
Ｆ信号を通過きせる第２フィルタと、該第２フィルタの
出力端に得られる前記映像ＩＦ信号にロックするＰＬＬ
回路と、該ＰＬＬ回路の出力信号を用いて前記第１フィ
ルタの出力端に得られる前記映像ＩＦ信号を同期検波す
る映像検波回路と、前記ＰＬＬ回路の出力信号と前記第
２フィルタの出力信号とを用いて映像搬送波と音声搬送
波の周波数に相当する４ 、 ５ ＭＢ２のビート成分
を取り出す乗算回路と、該乗算回路の出力信号をＦＭ検
波するＦＭ検波回路とからなることを特徴とする。(d) Means for Solving the Problems The present invention has been made in view of the above points, and includes a first filter that allows the video IF signal to pass, and a first filter that allows the video IF signal to pass through the video IF signal and the audio I/F signal.
a second filter that allows the F signal to pass; and a PLL that locks to the video IF signal obtained at the output end of the second filter.
a video detection circuit that synchronously detects the video IF signal obtained at the output end of the first filter using the output signal of the PLL circuit; and an output signal of the PLL circuit and an output signal of the second filter. It is characterized by comprising a multiplier circuit that extracts a beat component of 4,5 MB2 corresponding to the frequencies of a video carrier wave and an audio carrier wave using the FM detection circuit, and an FM detection circuit that performs FM detection on the output signal of the multiplier circuit.
（ホ）作用
本発明に依れば、第２フィルタの出力映像ＩＦ信号と該
出力映像ＩＦ信号の位相にロックしたＰＬＬ回路の出力
信号との乗算を行なって４ 、５ ＭＨｚのビート成分
を取り出して音声信号の復調を行なうことが出来る。ま
た前記ＰＬＬ回路の出力信号を用いて、第１フィルタか
ら得られる映像ＩＦ信号を検波する乙とが出来、単一の
ＰＬＬ回路で映像信号及び音声信号を検波することが出
来る。(e) Operation According to the present invention, the output video IF signal of the second filter is multiplied by the output signal of the PLL circuit locked to the phase of the output video IF signal, and the beat components of 4 and 5 MHz are extracted. It is possible to perform demodulation of the audio signal. Further, the output signal of the PLL circuit can be used to detect the video IF signal obtained from the first filter, and the video signal and the audio signal can be detected with a single PLL circuit.
（へ）実施例
第１図は、本発明の一実施例を示す回路図で、（１４）
は映像ＩＦ信号を通過させる第１ＳＡＷフイルク、（１
５）は音声ＩＦ信号及び映像ＩＦ信号を通過させる第２
３ＡＷフィルタ、（す）は位相比較器（１７）、ローパ
スフィルタ（１８）及びＶ ＣＯ（１９）から成るＰＬ
Ｌ回路、（２０）は音声ＩＦ増幅器り２１）の出力信号
とＶ ＣＯ（１９）の出力信号との乗算を行なう乗算回
路、（２２）はＶ ＣＯ（１９）の出力信号を移相する
移相量可変型の移相回路、（２３）は前記移相回路（２
２）の出力（ｇ号をπ／４移相するπ／４移相回路、（
２４）は映像ＩＦ増幅器（２５）の出力信号とπ／４移
相回路（２３）の出力信号とが印加される位相比較回路
、（２６）は前記位相比較回路（２４）の出力信号を平
滑し移相回路（２２）に印加するローパスフィルタ、（
２７）は前記移相回路（２２）の出力信号を−π／４移
相した信号に基づいて前記映像ＩＦ増幅器（２５）の出
力信号を同期検波する映像検波回路である。尚、第１Ｓ
ＡＷフィルタ（１４）のフィルタ特性は、映像搬送波周
波数がその減衰域に位置する様、設定きれている。(f) Embodiment FIG. 1 is a circuit diagram showing an embodiment of the present invention, (14)
is the first SAW film that passes the video IF signal, (1
5) is the second one that passes the audio IF signal and the video IF signal.
3AW filter, PL consisting of phase comparator (17), low pass filter (18) and V CO (19)
L circuit, (20) is a multiplier circuit that multiplies the output signal of the audio IF amplifier (21) and the output signal of V CO (19), and (22) is a shift circuit that shifts the phase of the output signal of V CO (19). A variable phase amount type phase shift circuit (23) is the phase shift circuit (23).
2) output (π/4 phase shift circuit that shifts the phase of g by π/4, (
24) is a phase comparison circuit to which the output signal of the video IF amplifier (25) and the output signal of the π/4 phase shift circuit (23) are applied, and (26) is a phase comparison circuit that smoothes the output signal of the phase comparison circuit (24). and a low-pass filter applied to the phase shift circuit (22), (
27) is a video detection circuit that synchronously detects the output signal of the video IF amplifier (25) based on a signal obtained by phase-shifting the output signal of the phase shift circuit (22) by -π/4. Furthermore, the 1st S
The filter characteristics of the AW filter (14) are set so that the video carrier frequency is located in its attenuation range.
第１図の回路において、チューナ（２８）の出力信号は
第１ＳＡＷフィルタ（１４）に印加きれ、前記出力信号
中の映像ＩＦ信号のみが取り出され、該映像ＩＦ信号は
映像ＩＦ増幅器（２５）にて増幅される。又、前記出力
信号は第２ＳＡＷフィルタ（１５）に印加され、前記出
力信号中の映像ＩＦ信号及び音声ＩＦ信号が取り出され
、前記映像及び音声ＩＦ信号が音声ＩＦ増幅器（２１）
にて増幅される。そして、音声ＩＦ増幅器（２１）の出
力信号は乗算回路（２０）及び位相比較回路（１７）に
印加される。位相比較回路（１７）は前記出力信号とＶ
ＣＯ（１９）の映像搬送波周波数の発振出力信号との
位相比較を行ない、両信号のき相差に応じた制御信号を
ローパスフィルタ（１８）を介してＶ ＣＯ（１９）に
印加する。すると、ｖＣＯ（１９）からは音声ＩＦ増幅
器（２１）（７）出力信号中の映像ＩＦ信号に位相がロ
ックした映像搬送波周波数の出力信号が発生する。その
為、乗算回路（２０）において音声ＩＦ増幅器（２１〉
の出力信号とＶ ＣＯ（１９）の出力信号との乗算が行
なわれると、音声搬送波と映像搬送波との周波数差に相
当する４ 、 ５ ＭＨｚのビート成分がその出力端に
得られる。そして、前記ビート成分はＦＭ検波回路（３
０）にてＦＭ検波され出力端子（３１）に音声信号が導
出される。In the circuit shown in FIG. 1, the output signal of the tuner (28) is completely applied to the first SAW filter (14), and only the video IF signal in the output signal is taken out, and the video IF signal is sent to the video IF amplifier (25). is amplified. Further, the output signal is applied to a second SAW filter (15), a video IF signal and an audio IF signal in the output signal are extracted, and the video and audio IF signals are applied to an audio IF amplifier (21).
is amplified. The output signal of the audio IF amplifier (21) is then applied to the multiplication circuit (20) and the phase comparison circuit (17). The phase comparator circuit (17) is connected to the output signal and V
The phase is compared with the oscillation output signal of the video carrier frequency of the CO (19), and a control signal corresponding to the phase difference between the two signals is applied to the V CO (19) via the low-pass filter (18). Then, the vCO (19) generates an output signal of a video carrier frequency whose phase is locked to the video IF signal among the output signals of the audio IF amplifiers (21) (7). Therefore, in the multiplication circuit (20), the audio IF amplifier (21)
When the output signal of VCO (19) is multiplied by the output signal of VCO (19), a beat component of 4.5 MHz corresponding to the frequency difference between the audio carrier wave and the video carrier wave is obtained at its output end. Then, the beat component is detected by the FM detection circuit (3).
0), and an audio signal is derived to an output terminal (31).
尚、この時Ｖ ＣＯ（１９）の出力信号の位相を音声Ｉ
Ｆ増幅器（２１〉の出力映像ＩＦ信号の位相とπ／２異
ならせれば、乗算回路（２０）において映像信号成分が
検出されず、後段のＦＭ検波回路（３０）等にダイナミ
ックレンジでの悪影響を与えない。At this time, the phase of the output signal of V CO (19) is
If the phase is different from the output video IF signal of the F amplifier (21) by π/2, the video signal component will not be detected in the multiplier circuit (20), which will adversely affect the dynamic range of the subsequent FM detection circuit (30), etc. I won't give it.
第２フィルタ（１５）のフィルタ特性は第３図（ロ）の
如きものである。図から明らかな様に映像信号成分はフ
ィルタの位相変調の影響を受けずに通過出来る。従って
、Ｖ ＣＯ（１９）の出力信号を正しい位相の映像搬送
波に同期させることが出来、′その発振周波数も映像搬
送波周波数と等しくなる。一方、Ｖ ＣＯ（１９）の出
力信号は移相回路（２２）にて所定移相された後、更に
π／４移相回路（２３）で＋π／４移相させられ、位相
比較回路（２４）に印加される。すると、位相比較回路
（２４〉において、前記出力信号と映像ＩＦ増幅器（２
５〉からの映像搬送波信号との位相比較が行なわれ、両
信号の位相差に応じた制御信号がローパスフィルタ＜２
６）を介して移相回路（２２）に印加され移相回路（２
２）の移相量が所定位相となる。その結果、移相回路（
２２）の出力信号は所定移相させられ、−π／４移相回
路（２８）で更に一π／４移相させられることにより、
映像検波回路（２７）の両人力信号間の位相差はπとな
る。The filter characteristics of the second filter (15) are as shown in FIG. 3 (b). As is clear from the figure, the video signal component can pass through without being affected by the phase modulation of the filter. Therefore, the output signal of the VCO (19) can be synchronized with the video carrier wave having the correct phase, and its oscillation frequency becomes equal to the video carrier frequency. On the other hand, the output signal of the V CO (19) is phase-shifted by a predetermined amount in a phase shift circuit (22), and then further phase-shifted by +π/4 in a π/4 phase shift circuit (23). ) is applied to Then, in the phase comparator circuit (24), the output signal and the video IF amplifier (24) are
A phase comparison is made with the video carrier signal from 5>, and a control signal corresponding to the phase difference between the two signals is passed through a low-pass filter
6) to the phase shift circuit (22).
The amount of phase shift 2) becomes the predetermined phase. As a result, the phase shift circuit (
The output signal of 22) is phase-shifted by a predetermined amount, and further phase-shifted by 1π/4 in the -π/4 phase shift circuit (28), so that
The phase difference between the two human input signals of the video detection circuit (27) is π.
その為、映像ＩＦ増幅器（２５）からの映像ＩＦ信号は
、映像検波回路（２７）にて、その位相及び周波数が前
記映像ＩＦ信号に一致した信号に基づき検波され、映像
信号が出力端子（２９）に導出される。Therefore, the video IF signal from the video IF amplifier (25) is detected by the video detection circuit (27) based on a signal whose phase and frequency match the video IF signal, and the video signal is sent to the output terminal (29). ) is derived.
尚、第１図の回路においては移相回路（２２）の出力信
号をπ／４移相回路（２３）及び−π／４移相回路（２
８）に印加することにより映像搬送波信号と位相が１８
０度異ｌ６信号を作成しているが、本発明はこれに限定
されるものでなく、例えば第４図に示す如く移相回路（
２２）の出力信号をπ／２移相回路（３０）を介して位
相比較回路（２４〉に印加するとともに前記出力信号を
直接映像検波回路（２７）に印加してもよい。In addition, in the circuit of FIG. 1, the output signal of the phase shift circuit (22) is transferred to the
8), the phase with the video carrier signal is 18
Although the 0 degree difference l6 signal is created, the present invention is not limited to this. For example, as shown in FIG. 4, a phase shift circuit (
The output signal of 22) may be applied to the phase comparison circuit (24>) via the π/2 phase shift circuit (30), and the output signal may also be directly applied to the video detection circuit (27).
（ト）発明の効果
以上述べた如く本発明によれば、音声信号を得る為の第
２フィルタの出力端に得られる映像ＩＦ信号にロックす
るＰＬＬ回路を設け、前記ＰＬ−Ｌ回路の出力信号を用
いて４ 、５ Ｍｌ（ｚのビート成分を取り出すととも
に映像検波を行なっているので理想的な状態で映像及び
音声信号の検波を行なう事が出来る。又、本発明によれ
ば単一のｖＣｏを用いて映像及び音声信号の検波を行な
うことが出来るので、ＩＣ化に最適である。(G) Effects of the Invention As described above, according to the present invention, a PLL circuit that locks to the video IF signal obtained at the output end of the second filter for obtaining an audio signal is provided, and the output signal of the PL-L circuit is Since the beat components of 4 and 5 Ml (z are extracted and video detection is performed using Since it is possible to perform detection of video and audio signals using this method, it is ideal for IC implementation.
第１図は、本発明の一実施例を示す回路図、第２図は従
来の検波回路を示す回路図、第３図はフィルタ特性を示
す特性図、及び第４図は本発明の別の実施例を示す回路
図である。
（１４）・・・第１ＳＡＷフィルタ、 （１５）・・
・第２３ＡＷフィルタ、 （す）・・・ＰＬＬ回路、
（２０）・・・乗算回路、 （２２）・・・移相回路、
（２４）・・・位相比較回路、（２６）・・・ローパ
スフィルタ、（２７）・・・映像検波回路、 （３０）
・・・ＦＭ検波回路。FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram showing a conventional detection circuit, FIG. 3 is a characteristic diagram showing filter characteristics, and FIG. 4 is a circuit diagram showing another embodiment of the present invention. FIG. 2 is a circuit diagram showing an example. (14)...first SAW filter, (15)...
・23rd AW filter, (su)...PLL circuit,
(20)...Multiplication circuit, (22)...Phase shift circuit,
(24)...Phase comparison circuit, (26)...Low pass filter, (27)...Video detection circuit, (30)
...FM detection circuit.
Claims (1)
ＩＦ信号及び音声ＩＦ信号を通過させる第２フィルタと
、該第２フィルタの出力端に得られる前記映像ＩＦ信号
にロックするＰＬＬ回路と、該ＰＬＬ回路の出力信号を
用いて前記第１フィルタの出力端に得られる前記映像Ｉ
Ｆ信号を同期検波する映像検波回路と、前記ＰＬＬ回路
の出力信号と前記第２フィルタの出力信号とを用いて映
像搬送波と音声搬送波の周波数に相当する４．５ＭＨｚ
のビート成分を取り出す乗算回路と、該乗算回路の出力
信号をＦＭ検波するＦＭ検波回路とからなることを特徴
とする検波回路。(1) a first filter that passes a video IF signal, a second filter that passes a video IF signal and an audio IF signal, and a PLL circuit that locks to the video IF signal obtained at the output end of the second filter; The image I obtained at the output end of the first filter using the output signal of the PLL circuit.
A video detection circuit that synchronously detects the F signal, an output signal of the PLL circuit, and an output signal of the second filter are used to generate a frequency of 4.5 MHz corresponding to the frequency of the video carrier wave and the audio carrier wave.
1. A detection circuit comprising: a multiplication circuit that extracts a beat component of the multiplication circuit; and an FM detection circuit that performs FM detection on the output signal of the multiplication circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62010722A JP2552470B2 (en) | 1987-01-20 | 1987-01-20 | Detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62010722A JP2552470B2 (en) | 1987-01-20 | 1987-01-20 | Detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63179672A true JPS63179672A (en) | 1988-07-23 |
| JP2552470B2 JP2552470B2 (en) | 1996-11-13 |
Family
ID=11758177
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62010722A Expired - Lifetime JP2552470B2 (en) | 1987-01-20 | 1987-01-20 | Detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2552470B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01300772A (en) * | 1988-05-30 | 1989-12-05 | Mitsubishi Electric Corp | Video intermediate frequency signal processing circuit |
| US5644368A (en) * | 1994-11-30 | 1997-07-01 | Sony Corporation | Composite signal detecting apparatus having associated filter |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS583378A (en) * | 1981-06-29 | 1983-01-10 | Hitachi Ltd | Detector for television signal |
-
1987
- 1987-01-20 JP JP62010722A patent/JP2552470B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS583378A (en) * | 1981-06-29 | 1983-01-10 | Hitachi Ltd | Detector for television signal |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01300772A (en) * | 1988-05-30 | 1989-12-05 | Mitsubishi Electric Corp | Video intermediate frequency signal processing circuit |
| US5644368A (en) * | 1994-11-30 | 1997-07-01 | Sony Corporation | Composite signal detecting apparatus having associated filter |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2552470B2 (en) | 1996-11-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |