Demodulation system with dropout correction
AssigneeTED Bildplatten Aktiengesellschaft AEG-Telefunken-Teldec
InventorsGerhard Dickopp, Manfred Potter, Otto Brehm
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Abstract
A demodulation system of a playback device for a carrier frequency signal containing both useful information in the zero passages of the signal and signal break-ins which occur in the playback device. The system includes a limiter for limiting in an asymmetrical manner a signal fed to it and a demodulator coupled to the output of the limiter. A highpass filter is connected between the limiter and the demodulator so as to couple the output signal from the limiter to the demodulator. The highpass filter substantially passes only the useful information portion of the carrier signal and suppresses any break-ins introduced into the signal.
Claims7
In a demodulation system of a playback device for a carrier frequency signal, containing both useful information in the passages thereof through its zero amplitude value and signal break-ins occurring in the playback device, the system including a first highpass filter connected to receive the signal, a limiter for limiting a signal fed thereto in a manner which is not completely symmetrical, said limiter being coupled to the output of said first filter, and a demodulator which uses the spacing between such zero passages as a criterion for demodulation coupled to the output of the limiter, the improvement comprising:
- a second highpass filter connected between said limiter and said demodulator for coupling signals from said limiter to said demodulator and substantially passing only the useful information portion of the signal and suppressing the signal break-ins, said second filter having a frequency limit in the vicinity of the lowest lower sideband frequency to be transmitted through the demodulation system.
Dependencies are inferred from the claim text.