JPH0328816U

JPH0328816U -

Info

Publication number: JPH0328816U
Application number: JP8960489U
Authority: JP
Priority date: 1989-07-29
Filing date: 1989-07-29
Publication date: 1991-03-22

Description

[Brief explanation of the drawing]

第１図は本考案の一実施例の回路図、第２図は
本考案回路の要部の等価回路図、第３図は従来の
一例の回路図、第４図は可変容量ダイオードの印
加電圧対容量特性図である。１……変調信号入力端子、２……チヤンネル同
調電圧入力端子、３……出力端子、４……ＤＣ固
定バイアス回路、Ｌｘ……コイル、Ｄ_ｃ１，Ｄ_ｃ
２……可変容量ダイオード、Ｃ……コンデンサ、
Ｌ……誘導成分、Ｃ_ｔ１，Ｃ_ｔ２……各チヤネル
同調時の容量成分。 Figure 1 is a circuit diagram of an embodiment of the present invention, Figure 2 is an equivalent circuit diagram of the main parts of the circuit of the present invention, Figure 3 is a circuit diagram of a conventional example, and Figure 4 is the voltage applied to the variable capacitance diode. FIG. 3 is a capacitance characteristic diagram. 1... Modulation signal input terminal, 2... Channel tuning voltage input terminal, 3... Output terminal, 4... DC fixed bias circuit, Lx... Coil, D _c1 , D _{c
2} ...variable capacitance diode, C...capacitor,
L: Inductive component, C _t1 , C _t2 : Capacitive component when each channel is tuned.

Claims

[Claims for Utility Model Registration] A series connection between a coil and a first variable capacitance diode, and a series connection between a capacitor and a second variable capacitance diode are connected in parallel, and the inductive component and capacitance of the LC resonant circuit are respectively component, fix a DC bias at the connection point between the coil and the first variable capacitance diode, supply a modulation signal to vary the inductive component, and change the inductive component between the capacitor and the second
An FM modulation circuit configured to apply a channel tuning voltage to a connection point with a variable capacitance diode to vary the capacitance component.