JPH0165565U

JPH0165565U -

Info

Publication number: JPH0165565U
Application number: JP1987161554U
Authority: JP
Priority date: 1987-10-22
Filing date: 1987-10-22
Publication date: 1989-04-26
Also published as: JPH0354463Y2

Description

[Brief explanation of the drawing]

第１図は、本考案に係るテレビ音声多重放送受
信装置の判別回路の一実施例を示すブロツク図、
第２図は、本考案に係るテレビ音声多重放送受信
装置の判別回路に用いられるＰＬＬ回路の特性を
示す図、第３図は、ＦＭステレオ信号のスペクト
ルを示す図、第４図は、テレビ音声多重放送信号
のスペクトルを示す図、第５図は、従来のＰＬＬ
回路の特性を示す図、第６図は、本考案に係るテ
レビ音声多重放送受信装置の判別回路の要部を説
明する為の一部具体化した一実施例を示す回路で
ある。１：入力端子、２：低域通過フイルタ、３：帯
域通過フイルタ、４：ＦＭ検波回路、５：増幅回
路、６：マトリツクス回路、７，８：増幅回路、
９，１０：スピーカ、１１：判別回路、１２：リ
ミツタ回路、１３：位相比較回路、１４：低域通
過フイルタ、１５：電圧制御発振器、１６：位相
比較回路、１７：位相シフト回路、１８：レベル
調整回路、１９：ヒステリシス比較器、２０：表
示灯駆動回路、２１：ロジツク回路、２２：制御
端子、２３：ＶＣＯキラー端子、２４：発光ダイ
オード、２５：差動増幅回路、３３：電流ミラー
回路、３８，４２：定電流源回路。 FIG. 1 is a block diagram showing an embodiment of a discrimination circuit of a television audio multiplex broadcast receiving apparatus according to the present invention;
FIG. 2 is a diagram showing the characteristics of the PLL circuit used in the discrimination circuit of the TV audio multiplex broadcast receiving device according to the present invention, FIG. 3 is a diagram showing the spectrum of an FM stereo signal, and FIG. 4 is a diagram showing the spectrum of the TV audio signal. A diagram showing the spectrum of a multiplex broadcast signal, FIG. 5, shows a conventional PLL.
FIG. 6, which is a diagram showing the characteristics of the circuit, is a circuit showing an embodiment in which a part of the discriminating circuit of the television audio multiplex broadcast receiving apparatus according to the present invention is made concrete for explaining the main part thereof. 1: input terminal, 2: low pass filter, 3: band pass filter, 4: FM detection circuit, 5: amplifier circuit, 6: matrix circuit, 7, 8: amplifier circuit,
9, 10: Speaker, 11: Discrimination circuit, 12: Limiter circuit, 13: Phase comparison circuit, 14: Low pass filter, 15: Voltage controlled oscillator, 16: Phase comparison circuit, 17: Phase shift circuit, 18: Level Adjustment circuit, 19: Hysteresis comparator, 20: Indicator lamp drive circuit, 21: Logic circuit, 22: Control terminal, 23: VCO killer terminal, 24: Light emitting diode, 25: Differential amplifier circuit, 33: Current mirror circuit, 38, 42: Constant current source circuit.

Claims

[Scope of Claim for Utility Model Registration] (1) Deriving the sub-channel signal in a discrimination circuit of a television audio multiplex broadcast receiving device that can detect and derive the sub-channel signal of the television audio multiplex signal using a PLL circuit. a limiter circuit that limits the signal that has passed through the band pass filter, a PLL circuit to which the output from the limiter circuit is supplied, and a capture range of the PLL circuit after detecting the arrival of the sub-channel signal. What is claimed is: 1. A discrimination circuit for a television audio multiplex broadcast receiving device, characterized in that it includes means for expanding the lock range. (2) Before the sub-channel signal arrives, the means:
By reducing the output level of the limiter circuit, the PL
After the PLL circuit detects the sub-channel signal by narrowing the capture range and lock range of the L circuit, increase the output level of the limiter circuit to narrow the capture range and lock range of the PLL circuit to the sub-channel signal. 2. A discriminating circuit for a television audio multiplex broadcast receiving apparatus according to claim 1, characterized in that the discriminating circuit extends to substantially the same frequency bandwidth as the frequency bandwidth of the utility model registration claim 1.