JPS59169145U

JPS59169145U - AM Chuna

Info

Publication number: JPS59169145U
Application number: JP6340683U
Authority: JP
Inventors: 智博竹川
Original assignee: パイオニア株式会社
Priority date: 1983-04-26
Filing date: 1983-04-26
Publication date: 1984-11-12

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図は従来のＡＭチューナ回路の回路図、第２図は第
１図のＡＭチューナ回路において、ＬＷとＭＷのどちら
か一方が電波と同調しているときにＬＷとＭＷの切換を
行なったときのＡ点のＤＣレベルの変動を示す図、第３
図はこの考案のＡＭチューナの一実施例を示すブロック
図である。１・・・・・・フロントエンド、２・・・・・・中間周
波増幅回路、３・・・・・・検波回路、４・・・・・・
ＡＧＣ回路、５・・・・・・バイパスフィルタ、６．　
７・・・・・・トランスタ、８・・・・・・スイッチ。Figure 1 is a circuit diagram of a conventional AM tuner circuit, and Figure 2 shows the AM tuner circuit of Figure 1, in which switching between LW and MW is performed when either LW or MW is in tune with the radio wave. Figure 3 shows the fluctuation of the DC level at point A when
The figure is a block diagram showing an embodiment of the AM tuner of this invention. 1...Front end, 2...Intermediate frequency amplification circuit, 3...Detection circuit, 4...
AGC circuit, 5... Bypass filter, 6.
7...transistor, 8...switch.

Claims

[Scope of utility model registration request]

In an AM tuner that has a switching function between a low band and a medium band, two fixed contacts and a common movable contact are switched in conjunction with the long wave band and medium wave band changeover switch, and have a potential difference at the time of switching. a bypass filter that is connected to the movable contact of this switch and that detects and outputs the fluctuation in the potential difference between the two fixed contacts; and the bypass filter's output turns on and connects the output terminal of the AM tuner to ground potential. The AM tuner consists of a transistor that reduces the shock noise caused by switching the above-mentioned changeover switch to ground.