JPS58173021U - Dropout detection circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the connection of a dropout detection circuit in a reproduction brightness signal processing circuit for a VTR;
This figure is a diagram of a conventional dropout detection circuit, and FIG. 3 is a diagram showing the timing of an FM input signal input to the dropout detection circuit and a dropout pulse outputted. FIG. 4 is a dropout detection circuit diagram of one embodiment of this invention, and FIG. 5 is a waveform diagram showing the timing of the input FM signal and output dropout pulse in FIG. 4. In the figure, 7 is a dropout detection circuit, 11 is an input terminal, 12 is a detector, 13 is an output terminal, 14 is a detector filter, 15 is a capacitor filter, 16 is a switching transistor, and 18 is a discharge switching transistor.

Claims (2)

[Scope of utility model registration request] (1) A detector that has an input terminal and an output terminal and detects a reproduced FM signal input from the input terminal, and a detector filter that is connected to the detector and smoothes the detected output to produce a dropout detection signal. A dropout detection circuit comprising: a delay circuit connected to the detector to delay the end of the dropout detection signal from the end of the dropout section of the reprinted FM signal. (2) The delay circuit includes a dropout detection signal delay capacitor connected in parallel to the detector filter;
Registration of a utility model, characterized in that it comprises a first switching means that turns on the capacitor in that section in response to detection of a dropout detection signal, and a second switching means that discharges the capacitor except in the section. A dropout detection circuit according to claim 1.