Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1984-12-13
1987-01-27
Buczinski, Stephen C.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358118, H04N 7167, H04K 102
Patent
active
046397779
ABSTRACT:
Of the scrambling systems used in CATV and direct satellite broadcasting systems, the invention pertains to the transmission of a keying signal for demodulation. The keying signal, as a carrier wave displaced 90.degree. in phase from a picture carrier wave, is superimposed on the conventional sync signal suppression period with no sound carrier wave being processed, thereby avoiding the generation of buzzing noise which would occur when the keying signal is superimposed on the sound carrier wave. With this invention, not only can the generation of buzzing noises be eliminated, but also even in multiplex sound systems the sound signal can be transmitted without the sound quality being adversely affected. Also, no synchronizing signal can readily and easily be detected and, therefore, subscription TV programs can not be viewed by unauthorized persons.
REFERENCES:
patent: 3999005 (1976-12-01), Dickinson
patent: 4034402 (1977-07-01), Brian
patent: 4336553 (1982-06-01), den Toonder et al.
patent: 4338628 (1982-07-01), Payne et al.
patent: 4396946 (1983-08-01), Bond
patent: 4467353 (1982-03-01), Citta et al.
Buczinski Stephen C.
Koltak Melissa
Matsushita Electric - Industrial Co., Ltd.
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