Payview Limited

Other

William S Cheung

A television signal generator for producing a composite RF signal without high level intermodulation products. A signal network is provided to linearly combine a first video modulated carrier signal and a second carrier frequency of the same frequency modulated with an audio modulated subcarrier. An audio subcarrier generator is disclosed having a ceramic resonator for a frequency determining circuit element. The resonator is parallel connected with a voltage sensitive reactance element to provide a frequency modulated subcarrier in response to a modulating voltage.

Apparatus for producing audio and visual signals for modulating a

Apparatus for encoding and decoding information. Multiple scrambling techniques are provided to prevent unauthorized reception of a television picture signal. A first mode of scrambling provides for shifting randomly occurring horizontal synchronization pulses within each field of video signal producing horizontal as well as vertical instability. Video line inversion of selected lines within a field comprises a second mode of scrambling of the signal. A third mode of scrambling provides for amplitude shifting the television signal during selected portions of the signal which contains luminance and chrominance information following a line synchronization pulse.

Apparatus for encoding and decoding information

A vehicle ignition system comprises a transformer having a primary winding and a secondary winding for providing the desired high voltage to the spark plug of the vehicle engine and a circuit including a further winding for said transformer connected across a switch and a load. The switch is operable only by a security device and when it is closed, the load absorbs energy from the transformer so that insufficient voltage is generated at the spark plug and the vehicle is immobilized. The load can be replaced by a reverse flux generator, the reverse flux opposing that generated by the primary winding. The security device may comprise a conventional key and keyhole, or more sophisticated devices such as code readers which read a code inputted from a magnetic card or from a keyboard. Further security may be provided by a further switch in series with the primary winding and battery, the further switch being operable in synchronism with and in the opposite sense to the first mentioned switch.

Vehicle ignition system

During non-program hours, a subscription broadcast television station broadcasts in place of programming the time of a future special broadcast as well as other information to enable decoding circuitry of subscribers. The receiver at the subscriber's residence tunes during non-broadcast hours all subscription television broadcast frequencies, and compares the subscriber's identification number with information being broadcast. When a coincidence between the received identification number being broadcast, and a stored identification number is obtained, the time of the future special broadcast is stored in a memory. At the time of a subscription broadcast identified in the memory, tuning data is recalled from a memory for tuning the receiver to receive the special broadcast. The subscriber's decoding apparatus is also activated permitting descrambling of the special program broadcast.

Transmitting and receiving apparatus for permitting the transmission and

A composite video signal containing an information portion and a synchronization pulse is encoded by shifting the level of the synchronization pulse and also by inverting the information portion. The encoding is switched on and off at a randomly chosen frequency, under the control of random number generator enabled at regular intervals. The encoded signal is transmitted with a data signal representing the random number so that a receiver can decode the received signal. The transmitted data can include details of undesired recipients, to disable their decoders. Applied to a pay TV system, the transmitted data can include the rate to be charged for the program and a billing mechanism at the receiver will meter the appropriate charge.

Apparatus for encoding of information

Information encoding apparatus comprises at least two modulators, each operating on a different channel, means for combining the outputs of the modulators, means for applying an information signal to the modulators for modulating the carrier waves in their channels according to the information signal, a random data terminal and means responsive to the random data signal to enable the combining means to receive a carrier wave modulated with said information from individual modulators in turn. The invention also includes transmitting apparatus for transmitting the encoded information together with a signal from the random data terminal and the invention also includes receiving apparatus for receiving and decoding the information under the control of the random data signal extracted from the received signal.

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Hong Kong, China

William S Cheung