Abstract: 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.

Abstract: 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.