Patents by Inventor Stuart Keene Tewksbury

Stuart Keene Tewksbury has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4107669
    Abstract: An input analog signal is converted to a digital output signal by an oversampled predictive DPCM coder which includes an n stage delay line in the feedback loop. The n delay line outputs are weighted by coefficients a.sub.i . . . a.sub.n selected according to the relationship ##EQU1## AND THEN SUMMED. Alternatively, the feedback loop may comprise a chain of n integrators arranged so that the signal fed back to the comparator is the sum of single, double, triple . . . n order integration. By so doing, the coder attenuates the signal power at the quantizer input while the attenuator coefficients are independent of the input signal statistics.A similar technique may also be applied in an oversampled error feedback coder, which includes a feedback loop having an n stage delay line. Here again, the delay line outputs are weighted in accordance with the above relationship. Alternatively, a chain of n integrators may be used in the coder input, and an identical chain employed in the feedback loop.
    Type: Grant
    Filed: January 3, 1977
    Date of Patent: August 15, 1978
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Stuart Keene Tewksbury
  • Patent number: 4071842
    Abstract: An input analog signal is converted to a digital output signal by an oversampled predictive DPCM coder which includes an n stage delay line in the feedback loop. The n delay line outputs are weighted by coefficients a.sub.i . . . a.sub.n selected according to the relationship ##EQU1## AND THEN SUMMED. Alternatively, the feedback loop may comprise a chain of n integrators arranged so that the signal fed back to the comparator is the sum of single, double, triple...n order integration. By so doing, the coder attenuates the signal power at the quantizer input while the attenuator coefficients are independent of the input signal statistics.A similar technique may also be applied in an oversampled error feedback coder, which includes a feedback loop having an n stage delay line. Here again, the delay line outputs are weighted in accordance with the above relationship. Alternatively, a chain of n integrators may be used in the coder input, and an identical chain employed in the feedback loop.
    Type: Grant
    Filed: January 3, 1977
    Date of Patent: January 31, 1978
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Stuart Keene Tewksbury
  • Patent number: 4017849
    Abstract: An input analog signal is converted to a digital output signal by an oversampled predictive DPCM coder which includes an n stage delay line in the feedback loop. The n delay line outputs are weighted by coefficients a.sub.i. . . a.sub.n selected according to the relationship ##EQU1## AND THEN SUMMED. Alternatively, the feedback loop may comprise a chain of n integrators arranged so that the signal fed back to the comparator is the sum of single, double, triple . . . n order integration. By so doing, the coder attenuates the signal power at the quantizer input while the attenuator coefficients are independent of the input signal statistics.A similar technique may also be applied in an oversampled error feedback coder, which includes a feedback loop having an n stage delay line. Here again, the delay line outputs are weighted in accordance with the above relationship. Alternatively, a chain of n integrators may be used in the coder input, and an identical chain employed in the feedback loop.
    Type: Grant
    Filed: August 28, 1975
    Date of Patent: April 12, 1977
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Stuart Keene Tewksbury