JPS61189671U

JPS61189671U -

Info

Publication number: JPS61189671U
Application number: JP7338285U
Authority: JP
Priority date: 1985-05-17
Filing date: 1985-05-17
Publication date: 1986-11-26

Description

[Brief explanation of the drawing]

第１図は本考案にかかる高周波回路、第２図は
第１図の高周波回路によりＶＴＲチユーナに印加
する信号レベルの特性図、第３図は従来の高周波
回路、第４図は従来回路によりＶＴＲチユーナに
印加する信号レベルの特性図である。１１……ＲＦモジユレータ、１２……電圧入力
回路、１３……増幅器、１４……第１の電子スイ
ツチ、１５……分配器、１６……第２の電子スイ
ツチ、２１……第３の電子スイツチ、Ａ……アン
テナ入力端子、Ｂ……ＶＴＲチユーナへの出力端
子、Ｃ……ＴＶ受信機への出力端子、Ｆ……ＲＦ
モジユレータ電源端子、Ｄ１〜Ｄ４……ダイオー
ド。 Fig. 1 shows a high frequency circuit according to the present invention, Fig. 2 shows a characteristic diagram of the signal level applied to a VTR tuner by the high frequency circuit shown in Fig. 1, Fig. 3 shows a conventional high frequency circuit, and Fig. 4 shows a VTR tuner applied to a VTR tuner by the conventional circuit. FIG. 3 is a characteristic diagram of a signal level applied to a tuner. 11...RF modulator, 12...Voltage input circuit, 13...Amplifier, 14...First electronic switch, 15...Distributor, 16...Second electronic switch, 21...Third electronic switch , A...Antenna input terminal, B...Output terminal to VTR tuner, C...Output terminal to TV receiver, F...RF
Modulator power supply terminals, D1 to D4...diodes.

Claims

[Claims for Utility Model Registration] (1) A antenna which supplies the first antenna input signal via a distributor to a tuner of a video device, and which is disposed between the distributor and an output terminal to a television receiver. The conduction of the first electronic switch and the conduction of the second electronic switch disposed between the RF modulator and the output terminal are controlled so that the second antenna input signal via the distributor and the RF modulator are connected to each other. A high frequency circuit selectively outputs one of the output signals outputted from the electronic switch to a television receiver, the high frequency circuit is disposed between the distributor and the ground, and the first electronic switch is non-conducting and the second electronic switch is non-conducting. A high frequency circuit comprising a third electronic switch that is conductive when the electronic switch is conductive. (2) The first and second electronic switches are composed of diodes, and further include voltage input means for applying a predetermined bias to each diode and controlling its conduction. The high frequency circuit described in (1). (3) The third electronic switch is composed of a diode, the anode of the diode is connected to the connection point between the distributor and the first electronic switch via a capacitor, and the cathode is grounded, and Utility model registration Claim No. (2) characterized in that the bias voltage of the second electronic switch is applied to the anode of the diode.
High frequency circuit described in section. (4) A resistor connected in series with the diode of the third electronic switch so that the impedance of the connection point when the first electronic switch is conductive and the impedance of the connection point when the third electronic switch is conductive are approximately the same value. A high-frequency circuit according to claim (3) of the utility model registration, characterized in that the high-frequency circuit is formed by connecting the following.