Patents by Inventor Vishu R. Viswanathan

Vishu R. Viswanathan 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: 5694426
    Abstract: A new signal quantization scheme is proposed which reduces fluctuation of the output signal by a signal quantizer (10) providing a quantized output signal and multiplying (18) said input signal X by a factor (1-w.sub.1) and finding a difference signal .DELTA..sub.in (11) between both the input signal and the previous input signal and multiplying (16) that by a weighting factor w.sub.2 from a control (13). The previous quantizer output signal Q.sub.prev is summed (17) with the weighted difference signal .DELTA..sub.in w.sub.2 and the sum is weighted by a weighting factor w.sub.1 at a multiplier (19) to yield w.sub.1 (Q.sub.prev +w.sub.2 .DELTA..sub.in). This signal is then summed at an adder (21) and applied to the quantizer (10) so that the quantizer is forced to match the fluctuation in the input signal as well as the signal itself.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: December 2, 1997
    Assignee: Texas Instruments Incorporated
    Inventors: Alan V. McCree, Vishu R. Viswanathan
  • Patent number: 5641927
    Abstract: A Karaoke (10) apparatus with autokeying is provided by measuring the average pitch (28) of the singer or user over a predetermined time period, comparing (29) the pitch of the singer or user voice to that of a reference pitch to provide a signal representing mismatch and changing the pitch (31) of the background music to match that of the singer or user.
    Type: Grant
    Filed: April 18, 1995
    Date of Patent: June 24, 1997
    Assignee: Texas Instruments Incorporated
    Inventors: Basavaraj I. Pawate, Rabin Deka, Wallace Anderson, Wai-Ming Lai, Vishu R. Viswanathan
  • Patent number: 5568514
    Abstract: A new signal quantization scheme is proposed which reduces fluctuation of the output signal by a signal quantizer (10) providing a quantized output signal and multiplying (18) said input signal X by a factor (1-w.sub.1)and finding a difference signal .DELTA..sub.in (11) between both the input signal and the previous input signal and multiplying (16) that by a weighting factor w.sub.2 from a control (13). The previous quantizer output signal Q.sub.prev is summed (17) with the weighted difference signal .DELTA..sub.in w.sub.2 and the sum is weighted by a weighting factor w.sub.1 at a multiplier (19) to yield w.sub.1 (Q.sub.prev +w.sub.2 .DELTA..sub.in). This signal is then summed at an adder (21) and applied to the quantizer (10) so that the quantizer is forced to match the fluctuation in the input signal as well as the signal itself.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: October 22, 1996
    Assignee: Texas Instruments Incorporated
    Inventors: Alan V. McCree, Vishu R. Viswanathan
  • Patent number: 5487087
    Abstract: A new signal quantization scheme is proposed which reduces fluctuation of the output signal by a signal quantizer (10) providing a quantized output signal and multiplying(18) said input signal X by a factor (1-w.sub.1)and finding a difference signal .DELTA..sub.n (11) between both the input signal and the previous input signal and multiplying (16) that by a weighting factor w.sub.2 from a control (13). The previous quantizer output signal Q.sub.prev is summed (17) with the weighted difference signal .DELTA..sub.in w.sub.2 and the sum is weighted by a weighting factor w.sub.1 at a multiplier (19) to yield w.sub.1 (Q.sub.prev +w.sub.2 .DELTA..sub.in). This signal is then summed at an adder (21) and applied to the quantizer (10) so that the quantizer is forced to match the fluctuation in the input signal as well as the signal itself. When applied to speech encoding algorithms such as the North American digital cellular telephone standard VSELP, the new quantizer results in more natural sounding background noise.
    Type: Grant
    Filed: May 17, 1994
    Date of Patent: January 23, 1996
    Assignee: Texas Instruments Incorporated
    Inventors: Alan V. McCree, Vishu R. Viswanathan
  • Patent number: 5353376
    Abstract: Systems and methods for improved speech acquisition are disclosed including a plurality of linearly arrayed sensors to detect spoken input and to output signals in response thereto, a beamformer connected to the sensors to cancel a preselected noise portion of the signals to thereby produce a processed signal, and a speech recognition system to recognize the processed signal and to respond thereto. The beamformer may also include an adaptive filter with enable/disable circuitry for selectively training the adaptive filter a predetermined period of time. A highpass filter may also be used to filter a preselected noise portion of the sensed signals before the signals are forwarded to the beamformer. The speech recognition system may include a speaker independent base which is able to be adapted by a predetermined amount of training by a speaker, and which system includes a voice dialer or a speech coder for telecommunication.
    Type: Grant
    Filed: March 20, 1992
    Date of Patent: October 4, 1994
    Assignee: Texas Instruments Incorporated
    Inventors: Sang G. Oh, Vishu R. Viswanathan