Accession Number : ADD018469

Title :   Digital Circuit for the Introduction of Dither into an Analog Signal.

Descriptive Note : Patent, Filed 8 Feb 95, patented 12 Nov 96,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Borgen, Gary S ; Sullivan, James L

Report Date : 08 Feb 1995

Pagination or Media Count : 18

Abstract : An electronics circuit for digitizing an analog audio data signal into a digital equivalent signal and then introducing digitized nyquist dither data into the digital equivalent signal to substantially eliminate the need for removing the nyquist dither data from the digital equivalent signal prior to its conversion to an analog signal which is a substantial replica of the incoming analog audio or like data signal. The electronics circuit comprises a first pseudo-random number generator which generates a series of digitized nyquist dither bits for addition to the digital equivalent signal. The digitized nyquist dither bits are in turn, provided by an external computer using a computer program which first generates a pseudo-random sequence of positive integers over a first predetermined range. The computer program implements a high pass filter which processes the pseudo-random sequence of positive integers to generate the digitized nyquist dither bits for use by the programmed read only memory as the dither bits to be added to the digital equivalent signal. A binary adder adds the digitized nyquist dither bits to the digital equivalent signal and then provides the resulting digital equivalent signal with dither to a first clipping circuit. The first clipping circuit clips the digital equivalent signal with dither to a maximum binary value having every bit at the logic one state and a minimum binary value having every bit at the logic zero state.

Descriptors :   *ANALOG TO DIGITAL CONVERTERS, *PATENTS, *CLIPPER CIRCUITS, ELECTRONICS, DATA TRANSMISSION SYSTEMS, COMPUTER PROGRAMMING, SEQUENCES, ACOUSTIC SIGNALS, ANALOG SIGNALS, HIGH PASS FILTERS, READ ONLY MEMORIES, PSEUDO RANDOM SYSTEMS, SIGNAL GENERATORS

Subject Categories : Electrical and Electronic Equipment
      Computer Hardware
      Telemetry
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE