JPS615065U

JPS615065U - RF modulator

Info

Publication number: JPS615065U
Application number: JP9004184U
Authority: JP
Inventors: 治大川内
Original assignee: 関西日本電気株式会社
Priority date: 1984-06-15
Filing date: 1984-06-15
Publication date: 1986-01-13

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図は本考案に係る実施例のＲＦモジュレータの回路
図、第２図は第１図の他の実施例の要部回路図、第３図
は従来例の回路図、及び第４図は特定チャンネル方式に
おける周波数スペクトル図である。２１・・・ビデイオ信号入力端子、２２・・・オーディ
オ信号入力端子、２３・・二ＲＦ変調信号出力端子、２
４・・・変調用ＩＣ，２５・・・共振素子、２６・・・
混合出力回路、２９．３０・・・トラップ回路、３１，
３３，３４・・・切換スイッチ、３２．４２・・・イン
ピーダンス直列回路、３５，４．１・・・スイッチング
ダイオード、３６，３７，４４・・・コンデンサ、４２
・・・抵抗、４３・・・コイル。FIG. 1 is a circuit diagram of an RF modulator according to an embodiment of the present invention, FIG. 2 is a main circuit diagram of another embodiment of FIG. 1, FIG. 3 is a circuit diagram of a conventional example, and FIG. It is a frequency spectrum diagram in a specific channel system. 21...Video signal input terminal, 22...Audio signal input terminal, 23...2 RF modulation signal output terminal, 2
4...Modulation IC, 25...Resonance element, 26...
mixed output circuit, 29.30... trap circuit, 31,
33, 34... Selector switch, 32.42... Impedance series circuit, 35, 4.1... Switching diode, 36, 37, 44... Capacitor, 42
...Resistance, 43...Coil.

Claims

[Scope of utility model registration request]

Video signal input terminal, audio signal input terminal, first
and a channel changeover switch that selects one of the second carrier waves, an oscillator that generates the carrier wave selected by the switch, an AM modulator that amplitude modulates the oscillation output with a signal from the video signal input terminal, and an AM modulator that modulates the amplitude of the oscillation output with the signal from the audio signal input terminal. an FM modulator that frequency-modulates the signal of the oscillator, a converter that frequency-converts the FM modulated output using the carrier wave of the oscillator, a trap circuit that removes the lower sideband of the frequency-converted output, and
In a modulator comprising an output circuit that mixes the output of the M modulator and the output of the trap circuit to generate an RF modulated output, the trap circuit includes at least one LC parallel resonant circuit and a circuit connected in parallel with the resonant circuit. An impedance series circuit including a switching diode is provided, and when one of the first and second carrier waves is selected, the switching diode is made conductive by the changeover switch to change the impedance of the series circuit to select a predetermined value regarding the one carrier wave. An RF modulator characterized in that it prevents drape removal of components of.