JPS58176269U

JPS58176269U - Automatic gain control circuit for tracking

Info

Publication number: JPS58176269U
Application number: JP7374982U
Authority: JP
Inventors: 潟渕　久志
Original assignee: 株式会社東芝
Priority date: 1982-05-20
Filing date: 1982-05-20
Publication date: 1983-11-25
Also published as: JPH0110786Y2

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of drawings]

第１図はビデオディスクのトラッキング情報及び切換情
報の記録形態を示す説明図、第２図はトラッキング情報
及び切換情報の検出回路を示す回路図、第３図はこの考
案の一実施例を示す回路図、第４図は第３図の自動利得
制御増幅器の具体回路図である。　　　　　　　　　′ ２６・・・・・・自動利得制御増幅器、２７ａ〜２７Ｃ
・・・・・・第１〜第３のバンドパスフィルタ、２８ａ
〜２８Ｃ・・・・・・第１・・・第３の検波器、２９・
・・・・・加算器、３０・・・・・・低域フィルタ、３
１・・・・・・モード検出装置、ＳＷ・・・・・・スイ
ッチ。FIG. 1 is an explanatory diagram showing the recording format of tracking information and switching information on a video disc, FIG. 2 is a circuit diagram showing a tracking information and switching information detection circuit, and FIG. 3 is a circuit showing an embodiment of this invention. 4 are specific circuit diagrams of the automatic gain control amplifier shown in FIG. 3. ' 26... Automatic gain control amplifier, 27a to 27C
...First to third band pass filters, 28a
~28C...First...Third detector, 29.
... Adder, 30 ... Low-pass filter, 3
1...Mode detection device, SW...Switch.

Claims

[Scope of utility model registration request]

First and second tracking information having mutually different frequencies are recorded along both sides of a spiral recording line of a disk-shaped recording medium, and the frequency relationship of the tracking information is recorded every revolution of the recording line, and the frequency relationship of the tracking information is the same as that of the inner circumference. an automatic gain control amplifier to which is input a reproduction signal of switching information for informing that the switching information has been changed between the side and the outer side; and an output of this automatic gain control amplifier is added to the first and second tracking. first, second, frequency-separating information and switching information;
a third bandpass filter; first, second, and third detectors that respectively detect the outputs of the first, second, and third bandpass filters; an adder for synthesizing the output; a low-pass filter for smoothing the output of the adder and applying it to a gain control terminal of the automatic gain control amplifier; and an amplification of the automatic gain control circuit when in a special reproduction mode for the disk-shaped recording medium. An automatic gain control circuit for tracking, comprising: means for suppressing a decrease in the output of the third detector by switching the ratio. □