Zenith Electronics Corporation

Mack S Daily

Caitlin B Bestler

Shu-Yuan V Yang

Thomas M Johnson

Thomas E Pennacchia

A method and apparatus for power tuning a terminal of a bi-directional communications system, such as a cable television plant. An iterative or cycle method is used to achieve a proper terminal transmitter power level at a remote terminal. A polling signal is transmitted in a downstream direction from a controller to the terminal. If the controller receives a status signal which is transmitted upstream from the terminal, then the controller compares a received power level measured at a head end against a predetermined range of acceptable power levels. If the power level is outside of the predetermined range, then the controller calculates and transmits a terminal transmitter power level in a downstream direction to the terminal. The iterative or cyclic method repeats until the received power level is within the predetermined range. If the received power level of the terminal remains outside of the predetermined range after a specified count of cycles or iterations or if the head end does not receive a status signal, then the controller either aborts the cycle or attempts to revive the terminal.

Method and apparatus for power tuning a terminal of a bi-directional

A television cable system includes a headend and a decoder coupled by an in-band communication link and an out of band communication link. The headend controller includes conventional transmission systems for providing a plurality of program channels to the decoder via the in-band communication link. In addition, the headend system includes a plurality of controller inputs which provide data to a download executive circuit which in turn organizes data and transfer it to a transmitter coupled to the out of band data link. Within the decoder, a pair of processors are operative via a communication link therebetween. One processor is of predefine capability and is used to operate a user keyboard as well as conventional tuning and signal processing and descrambling systems to provide television display. The remaining processor includes a memory manager coupled to an out of band transmission receiver which receives downloaded interpretive execution data. The decoder further includes a program memory and interpreter circuit operatively coupled to the memory manager. Downloaded data is presented to the interpreter by the dialogue processor which receives instructions in response from the interpreter to execute a particular instruction set or sequence group within the downloaded program. All instruction sets or sequence groups within the downloaded program are free of loops or branch backward instructions to avoid lockout problems.

System for cable communication wherein interpretively coded data

A television cable system includes a headend and a decoder coupled by an in-band communication link and an out of band communication link. The headend controller includes conventional transmission systems for providing a plurality of program channels to the decoder via the in-band communication link. In addition, the headend system includes a plurality of controller inputs which provide data to a download executive circuit which in turn organizes data and transfer it to a transmitter coupled to the out of band data link. Within the decoder, a pair of processors are operative via a communication link therebetween. One processor is of predefine capability and is used to operate a user keyboard as well as conventional tuning and signal processing and descrambling systems to provide television display. The remaining processor includes a memory manager coupled to an out of band transmission receiver which receives downloaded interpretive execution data. The decoder further includes a program memory and interpreter circuit operatively coupled to the memory manager. Downloaded data is presented to the interpreter by the dialogue processor which receives instructions in response from the interpreter to execute a particular instruction set or sequence group within the stored program. All instruction sets or sequence groups within the stored program are free of loops or branch backward instructions to avoid lockout problems.

Television distribution system having virtual memory downloading

A microprocessor communication system couples two microprocessors over a bus comprising a bidirectional data line, a bidirectional sync line and a pair of clock lines. A toggled clock signal serves as a control signal. Each microprocessor outputs data to the data and sync lines and monitors its incoming clock line. When a toggled clock signal is sensed, the receiving microprocessor, when its priorities permit, takes control of the bus and stops outputting data to the data and sync lines. It then detects the incoming data and when incoming data reception is completed, the microprocessor outputs new information to the data and sync lines and toggles its output clock line to signal to the other microprocessor that control of the bus has been relinquished. With the system, the microprocessors operate without the constraints of predetermined time intervals in which to output data or to receive data.

Controlling data transfer between two microprocessors by receiving input

A cable television system includes a headend unit having a plurality of program signal sources, encoders, scrambling circuits, and channel modulators for producing a plurality of program channels modulated at a corresponding plurality of cable system carrier frequencies. An address computer within the headend unit is operative upon the encoders to provide the insertion of a message packet within the vertical blanking interval of the program signals. The scrambler circuits render the program signal unviewable by conventional television receivers. A cable system decoder is coupled to the headend by a cable and includes a conventional tuner, intermediate frequency amplifier and detector. A decoder processor is coupled to a channel selection input and to the tuner to provide channel selection in accordance with a user input. The decoder processor examines the message packet during the vertical blanking interval to determine authorization of the decoder to display the received program channel. A descrambler is coupled to the processor and the tuner IF and detector to descramble the program signal if authorization is detected. A modulator modulates the descrambled signal upon a fixed channel carrier for application to a conventional television receiver.

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Round Lake Park, IL, United States of America

Mack S Daily