JPS59147338U

JPS59147338U - Detuned oscillation prevention circuit

Info

Publication number: JPS59147338U
Application number: JP4033483U
Authority: JP
Inventors: 今川　敏幸
Original assignee: クラリオン株式会社
Priority date: 1983-03-18
Filing date: 1983-03-18
Publication date: 1984-10-02

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 the drawing]

第１図は高周波増幅器の利得と周波数の関係を表わすダ
イヤグラム、第２図は本考案による離調発振防止回路を
含むラジオの増幅および検波部分のブロック図である。１・・・高周波増幅器、２・・・ミキサ回路、３・・・
局部発振器、４・・・第１中間周波増幅器、５・・・第
２中間周波増幅器、６・・・検波回路、７・・・デエン
ファシス回路、８・・・信号検出回路、９・・・倍電圧
整流回路、１０・・・電圧保持回路、１１・・・ＮＡＮ
Ｄ回路、１２・・・スイッチング・トランジスタ、１３
・・・低域通過フィルタ、Ｃ・・・コンデンサ、ＶＲ・
・・可変抵抗。FIG. 1 is a diagram showing the relationship between the gain and frequency of a high frequency amplifier, and FIG. 2 is a block diagram of the amplification and detection portion of a radio including the detuned oscillation prevention circuit according to the present invention. 1...High frequency amplifier, 2...Mixer circuit, 3...
Local oscillator, 4... First intermediate frequency amplifier, 5... Second intermediate frequency amplifier, 6... Detection circuit, 7... De-emphasis circuit, 8... Signal detection circuit, 9... Voltage doubler rectifier circuit, 10... Voltage holding circuit, 11... NAN
D circuit, 12... switching transistor, 13
・・・Low pass filter, C... Capacitor, VR・
...Variable resistance.

Claims

[Scope of utility model registration request]

a signal detection circuit, a rectification circuit that rectifies the output of the signal detection circuit, a voltage holding circuit that holds the output voltage of the rectification circuit for a predetermined time, and an output of the rectification circuit and an output of the voltage holding circuit. It includes an input NAND circuit, and a switching transistor whose emitter is grounded, whose collector is connected via a capacitor to a de-emphasis circuit provided after the detection circuit, and whose base is connected to the output of the NAND circuit. A detuning oscillation prevention circuit for μ tuner radios, which bypasses high-frequency components contained in an audio signal to ground when changing from tuning to detuning or vice versa.