JPS6128274B2 - - Google Patents
Info
- Publication number
- JPS6128274B2 JPS6128274B2 JP54128952A JP12895279A JPS6128274B2 JP S6128274 B2 JPS6128274 B2 JP S6128274B2 JP 54128952 A JP54128952 A JP 54128952A JP 12895279 A JP12895279 A JP 12895279A JP S6128274 B2 JPS6128274 B2 JP S6128274B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- preamplifier
- emitter
- video head
- color
- 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
- 230000001172 regenerating effect Effects 0.000 description 5
- 238000013016 damping Methods 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/79—Processing of colour television signals in connection with recording
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/42—Modifications of amplifiers to extend the bandwidth
- H03F1/48—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
Description
【発明の詳細な説明】
本発明は磁気記録再生装置（VTR）における
映像信号再生回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video signal reproducing circuit in a magnetic recording/reproducing apparatus (VTR).
従来VTRの再生回路において、ビデオヘツド
に誘起される信号は輝度信号情報を有するFM信
号レベルと比較してカラー信号レベルが小さいこ
と、またビデオヘツドのインダクタンスとこれに
並列接続されたキヤパシタンスとのピーキング特
性によりFM信号が強調されて再生されることな
どにより再生増幅器の出力点では、FM信号が所
定のレベルを得たとしてもカラー信号は所定のレ
ベルに達していないという問題がある。従つて従
来カラー信号は再生増幅器の出力からローパスフ
イルタによつてとりだし、再生カラー増幅器に入
力して所望の信号レベルを得た後ACC回路に印
加する必要があつた。 In conventional VTR playback circuits, the color signal level of the signal induced in the video head is lower than the FM signal level containing luminance signal information, and the peaking of the video head inductance and capacitance connected in parallel with it is also a problem. There is a problem in that the color signal does not reach the predetermined level at the output point of the regenerative amplifier even if the FM signal reaches a predetermined level because the FM signal is emphasized and reproduced due to its characteristics. Therefore, in the past, it was necessary to extract the color signal from the output of the regenerative amplifier using a low-pass filter, input it to the regenerative color amplifier, obtain the desired signal level, and then apply it to the ACC circuit.
本発明の目的は上記した従来技術の欠点をなく
し、再生増幅器出力点で十分なレベルのカラー信
号を得て再生カラー増幅器を不要にするととも
に、FM信号とカラー信号の両成分をプリアンプ
IC（映像信号再生用の集積回路）の共通端子よ
り出力することを可能にすることにある。 The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, obtain a color signal of sufficient level at the output point of the regenerative amplifier, eliminate the need for a regenerative color amplifier, and preamplify both the FM signal and color signal components.
The purpose is to enable output from a common terminal of an IC (integrated circuit for reproducing video signals).
本発明は初段増幅器の出力を入力部へ十分負帰
還しダンピングすることでカラー信号とFM信号
のレベルを揃え次段増幅器で所望のカラー信号、
FM信号レベルを得てエミツタフオロワを介して
出力し、ローパスフイルタの後に設けていた再生
カラー用増幅器を不要とするとともに、エミツタ
フオロワの出力信号をFM再生等化のためのピー
キング回路接続用として共通に用いるようにした
ものである。 The present invention provides sufficient negative feedback and damping of the output of the first-stage amplifier to the input section to equalize the levels of the color signal and FM signal, so that the next-stage amplifier outputs the desired color signal,
Obtains the FM signal level and outputs it via the emitsuta follower, eliminating the need for the reproduction color amplifier installed after the low-pass filter, and also using the output signal of the emitsuta follower commonly for connecting the peaking circuit for FM reproduction equalization. This is how it was done.
図は本発明の一実施例を示す回路図である。図
において１はビデオヘツド、２は巻線比１：２の
ロータリトランス、３はヘツドピーキング用コン
デンサ、４はIC入力端子、５は初段増幅器、６
はダンピング抵抗、７は後段増幅器、８はエミツ
タフオロワ、９はIC出力端子、１０，１１はそ
れぞれアース端子、および電源端子、１２はプリ
アンプIC、１３はローパスフイルタ、１５はFM
再生等化のための共振回路である。ヘツド１に誘
起される信号電圧は増幅器のノイズフイギユアを
劣化させないためにヘツド１のインダクタンスと
コンデンサ３のキヤパシタンスによる共振を利用
してFM搬送波のピーク周波数たとえば4.4MHz
でピーキングされ、端子４からプリアンプIC１
２に入力される。初段出力はダンピング抵抗６を
介して入力部へ負帰還され、前記したピーキング
特性がプリアンプとして本来もつべき再生等化特
性に対して支配的な影響を与えない範囲まで十分
ダンピングされる。これによつてカラー信号と
FM信号のレベル差は従来ピーキングされていた
分だけ圧縮され、カラー信号とFM信号の両成分
がそろつて、後の処理がしやすくなる。次に後段
増幅器７で、所定のレベルの信号に増幅し、エミ
ツタフオロワ出力端子９を共通端子として一方は
ローパスフイルタ１３を介してカラー信号成分１
４を出力し、他方は本来プリアンプとしてもつべ
き再生等化特性を得るためのFMピーキング回路
１５を介してFM信号１６を出力する。出力端子
９でのカラー信号レベルはすでに次のカラー信号
再生回路に必要なだけのレベルであり、従来用い
られていた再生カラー増幅器は不要となる。 The figure is a circuit diagram showing one embodiment of the present invention. In the figure, 1 is a video head, 2 is a rotary transformer with a winding ratio of 1:2, 3 is a head peaking capacitor, 4 is an IC input terminal, 5 is a first stage amplifier, and 6
is a damping resistor, 7 is a post-stage amplifier, 8 is an emitter follower, 9 is an IC output terminal, 10 and 11 are ground terminals and power supply terminals, respectively, 12 is a preamplifier IC, 13 is a low-pass filter, and 15 is FM
This is a resonant circuit for reproduction equalization. The signal voltage induced in head 1 is generated at the peak frequency of the FM carrier, for example 4.4 MHz, by using the resonance caused by the inductance of head 1 and the capacitance of capacitor 3 to avoid deteriorating the noise figure of the amplifier.
peaking from terminal 4 to preamplifier IC1.
2 is input. The first stage output is negatively fed back to the input section via the damping resistor 6, and is sufficiently damped to the extent that the peaking characteristics described above do not have a dominant effect on the reproduction equalization characteristics that the preamplifier should have. This results in a color signal and
The level difference in the FM signal is compressed by the amount that was conventionally peaked, and both the color signal and FM signal components are now aligned, making subsequent processing easier. Next, in the latter stage amplifier 7, the signal is amplified to a predetermined level, and the color signal component 1 is amplified to a predetermined level.
4, and the other outputs an FM signal 16 via an FM peaking circuit 15 for obtaining reproduction equalization characteristics that a preamplifier should originally have. The color signal level at the output terminal 9 is already at a level necessary for the next color signal reproducing circuit, and the conventionally used reproducing color amplifier becomes unnecessary.
以上のように本発明によれば、カラー信号及び
FM信号両成分を揃えてアンプしやすくなり、従
来用いられていたローパスフイルタの後の再生カ
ラー増幅器を必要としなくするとともにFM信号
とカラー信号の両成分を同一端子より出力できる
ため、ICのピン数が削減できる。 As described above, according to the present invention, color signals and
It becomes easier to amplify both FM signal components by aligning them, eliminating the need for a reproduction color amplifier after the conventionally used low-pass filter, and outputting both the FM signal and color signal components from the same terminal. The number can be reduced.
図は本発明による映像信号再生回路の一実施例
を示す回路図である。
１……ビデオヘツド、５……初段増幅器、６…
…ダンピング抵抗、７……後段増幅器、１３……
ローパスフイルタ、１５……FM再生等化回路。
The figure is a circuit diagram showing an embodiment of a video signal reproducing circuit according to the present invention. 1...Video head, 5...First stage amplifier, 6...
...Damping resistor, 7... Post-stage amplifier, 13...
Low-pass filter, 15...FM reproduction equalization circuit.
Claims (1)
ビデオヘツドに入力端子が接続されたプリアンプ
と、このプリアンプの出力信号がベースに導かれ
るエミツタフオロワとを具備し、上記ビデオヘツ
ドにより周波数変調信号とカラー信号が再生され
る磁気記録再生装置において、上記プリアンプの
出力信号をその入力端子に負帰還するための抵抗
と、上記エミツタフオロワのエミツタに接続され
たカラー信号抜き取り用ローパスフイルタと、上
記エミツタに接続された再生等化用ピーキング回
路とを具備し、上記ビデオヘツドのインダクタン
スを含めて上記プリアンプの出力端子側に生じる
共振回路を上記抵抗により十分ダンピングして上
記エミツタに出力されるカラー信号のレベルと周
波数変調信号のレベルとの差を抑えることを特徴
とする映像信号再生回路。1 A video head, a preamplifier whose input terminal is connected to the video head via a rotary transformer, and an emitter follower through which the output signal of the preamplifier is guided to the base, and the video head reproduces frequency modulated signals and color signals. A magnetic recording/reproducing apparatus comprising: a resistor for negative feedback of the output signal of the preamplifier to its input terminal; a low-pass filter for extracting color signals connected to the emitter of the emitter follower; and a reproduction etc. connected to the emitter. The resonant circuit generated on the output terminal side of the preamplifier, including the inductance of the video head, is sufficiently damped by the resistor, and the level of the color signal output to the emitter and the frequency modulation signal are adjusted. A video signal reproducing circuit characterized by suppressing the difference in level.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12895279A JPS5652986A (en) | 1979-10-08 | 1979-10-08 | Video signal regenerative circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12895279A JPS5652986A (en) | 1979-10-08 | 1979-10-08 | Video signal regenerative circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5652986A JPS5652986A (en) | 1981-05-12 |
| JPS6128274B2 true JPS6128274B2 (en) | 1986-06-30 |
Family
ID=14997460
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12895279A Granted JPS5652986A (en) | 1979-10-08 | 1979-10-08 | Video signal regenerative circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5652986A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59105786A (en) * | 1982-12-10 | 1984-06-19 | Hitachi Ltd | Preamplifier integrated circuit |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3513267A (en) * | 1966-05-16 | 1970-05-19 | Ampex | Low input impedance playback preamplifier for swamping out head resonance in a video tape reproducing system |
-
1979
- 1979-10-08 JP JP12895279A patent/JPS5652986A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3513267A (en) * | 1966-05-16 | 1970-05-19 | Ampex | Low input impedance playback preamplifier for swamping out head resonance in a video tape reproducing system |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5652986A (en) | 1981-05-12 |
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