Zenith Electronics Corporation

Gordon E Kelly

Mutsuo Nakanishi

Gopalan Krishnamurthy

Ted Elliott Hartson

Jouke N Rypkema

Richard G Merrell

An enclosure, including an automatic television signal switch, has four coaxial cable connectors, a first for bringing in an input television signal, a second and a third for supplying signals to and from a decoder, and a fourth for supplying television signals to a television receiver. A signal splitter is connected to the first connector and supplies one television signal to a decoder via the second connector and another television signal to a first stationary contact of a relay. The second relay stationary contact is connected to the third connector which receives decoded signals from the decoder. The movable contact of the relay is connected to the fourth connector. The relay is powered by an internal DC power supply that is connected via a line cord and plug to a switched AC power outlet on the decoder. Turning the decoder on automatically energizes the relay to pass input the television signal to the decoder. When the decoder is off, the relay bypasses the decoder and passes input television signals directly to the television receiver.

Decoder-operated television signal switch

A tilt correction circuit for a color television signal processor includes a differential amplifier having a first tuned circuit tuned near the color carrier frequency and a second tuned circuit tuned near the picture carrier frequency. An IF video input signal is applied to the differential amplifier, the output of which reflects the relative effect of the two tuned circuits. A correction voltage is derived by peak detecting the color burst and comparing it with a reference voltage related to a nominal color burst level in a color television signal. The correction voltage is supplied to the other input of the differential amplifier to change the relative effects of the tuned circuits to adjust the frequency response over the IF band. A tilt defeat circuit is included for disabling the correction voltage where the magnitude of the correction voltage indicates the presence of a monochrome signal.

Automatic frequency response correction using color burst

An STV system commonly transmits scrambled television signals which include encoded data reflecting subscriber address, authorization and program code information. In some STV systems the subscriber installation characteristically comprises a non-addressable converter for converting a transmitted RF signal to an output signal having the frequency of standard VHF television signal. The invention is addressed to an addressable adapter which responds to the output signal of the converter to render the subscriber installation addressable. To this end, the adapter comprises tuning means, data retrieval means and an addressable data processor for deriving, among other information, a decode enable signal. The decode enable signal is instrumental in deriving an unscrambled television signal from the converter output signal.

Adapter for rendering a non-addressable CATV converter addressable

An automatic homing system for a subscription television signal decoder comprises a tuning system responsive to a decoder off-command signal for operation in a search mode wherein successive television channels are sequentially tuned until a subscription television signal is detected. As a result, the memory circuits of the decoder may be refreshed with updated subscriber authorization data in response to a transmitted subscription television signal even though the decoder is turned off.

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Algonquin, IL, United States of America

Gordon E Kelly