Harris Corporation

Joseph Lee Seccia

Edwin Ray Twitchell

Ed Twitchell

Paul Henry Mizwicki

Bob Davis

Dave Nickell

A digital television transmitting system is presented having a recovery circuit for recovering non-return to zero (NRZ) data pulses and transport clock pulses from a biphase-mark serial data pulse stream and wherein the recovered NRZ data pulses and the recovered transport clock pulses are applied to modulation and amplifying circuits for broadcasting by an antenna. The recovery circuit includes a first circuit for receiving the biphase-mark serial pulse stream and providing therefrom a train of first clock pulses wherein the rising edge of each the biphase-mark pulse corresponds with a rising edge of one of the first clock pulses. A second circuit receives the biphase-mark serial data pulses and the first clock pulses for providing therefrom a train of de-serialized data pulses each having a rising edge corresponding with a rising edge of one of the first clock pulses. A third circuit receives the de-serialized data pulses and the first clock pulses and converts the de-serialized data pulses into recovered NRZ data pulses.

Digital television transmitting system having data and clock recovering circuit

A system and method for encoding via a trellis encoding scheme a digital data stream. The system and method finds particular application in the trellis encoding scheme used in the Grand Alliance digital television specification. In the system and method, a series of registers is used to cycle the digital bytes (or words) currently being interleaved and trellis encoded. A multiplexer selects the appropriate nibble of the data words for encoding during each cycle of the registers.

System and method for trellis encoding a digital signal

An exciter for advanced television signals such as a digital television signal. The exciter corrects for instabilities in the television signal provided to it so as to produce a signal with tightly controlled frequency and reduced co-channel interference. The exciter inserts a pilot frequency into the digital television signal after the signal has been shaped, thereby reducing the difficulties of shaping. Also disclosed is a rate converter for use in an exciter so that a digital signal can be received at a first frequency and can be output at a second frequency in a manner in which the output of a signal is assured even in the absence of an input signal.

System and Method for exciting advanced television signals

The present invention provides an apparatus for providing error correction data in a digital data transfer system. The apparatus receives a clock signal and provides a first signal using the clock signal. Information data is received and a second signal is provided using the information data. The information data is received in groups which each have a first predetermined number of elements. A plurality of &agr;ROMs provide Galois Field multiples in look-up tables. The &agr;ROMs are addressed using the first signal to provide a first address component and using the second signal to provide a second address component. Modula mathematics are performed utilizing the values from the &agr;ROMs to generate error correction data. The error correction data is in groups each having a second predetermined number of elements. A RAM is accessible by a Trellis encoder and has an array for holding the information data elements and error correction data elements. The number of array locations is equal to an integer multiple of the sum of the first and second predetermined numbers. Further, the information and error correction data elements are sent to the RAM in third groups. A first array location always receives a first element of one of the third groups of data. Thus, the data is easily interleaved by the Trellis encoder.

Apparatus for providing error correction data in a digital data transfer system

A test signal generator presents a test signal of pseudorandom data in a format which simulates the Grand Alliance Transmission Layer Signal for the 8- or 16- vestigial sideband (8/16-VSB) signal for Advanced Television (ATV) systems. An actual (non-test) Transmission Layer 8/16-VSB signal for ATV is in a particular format with properly formatted sync information and includes data which have been randomized, Reed-Solomon coded, interleaved, and trellis coded. The test signal generator provides data in the particular 8/16-VSB format which simulates the Grand Alliance transmission signal.

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Quincy, IL, United States of America

Joseph Lee Seccia