Signal trap, recording medium replay, and signal extraction device and method

Abstract

The invention provides a signal trap device and method. A replay signal reproduced from a video cassette tape is supplied directly to a subtracter while being fed to a fixed delay circuit and a variable delay circuit to be delayed therein by a predetermined delay time. The delayed signal is supplied also to the subtracter, which then subtracts the delayed signal from the reproduced replay signal and outputs the result of such subtraction therefrom. The delay time of the fixed delay circuit is set to correspond to the center frequency of the carrier of the desired FM signal to be trapped. Meanwhile the delay time of the variable delay circuit is so set as to correspond to the signal obtained by demodulating the desired FM signal. Thus, the desired FM signal can be trapped properly without any harmful influence on the other FM signal.

Description

technical field [0001] The present invention relates to a signal trapping device and method, a recording medium playback device and method, and a signal extraction device and method, especially suitable for separating audio FM signals recorded on magnetic tape from luminance FM signals. Background technique [0002] Figure 29 Displays the spectrum of a signal recorded on a tape in an 8mm tape video cassette recorder (trade name). As shown in the figure, an FM luminance signal obtained by modulating a predetermined carrier frequency with a luminance signal is recorded in the highest frequency band. The 743.444 KHz carrier, which is lower in frequency than the FM luminance signal, is amplitude modulated with the chrominance signal converted to a lower frequency. And in the frequency band further below the chrominance signal converted to the low frequency, a four-frequency tracking pilot signal (ATF signal) is provided. [0003] In addition, between the FM luminance signal a...

AI Technical Summary

Problems solved by technology

For this reason, when the AFM signal from the reproduced signal is notched, the low frequency band component of the YFM signal is also notched, thus lowering the resolution, with another disadvantage that it is almost impossible to obtain a high-quality image

[0009] Moreover, if the formed circuit only sharply traps the center frequency of the carrier of the AFM signal, the frequency offset corresponding to the FM signal produces an AM component, which eventually causes horizontal stripes, shadows on the screen

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