Jeffrey B Townsend

US Patent:

6556967, Apr 29, 2003

Filed:

Mar 12, 1999

Appl. No.:

09/266811

Inventors:

Douglas J. Nelson - Columbia MD
David C. Smith - Columbia MD
Jeffrey L. Townsend - Columbia MD

Assignee:

The United States of America as represented by the National Security Agency - Washington DC

International Classification:

G10L 1520

US Classification:

704233, 704226, 704227, 704228, 704208, 704214

Abstract:

The present invention is a device for and method of detecting voice activity by receiving a signal; computing the absolute value of the signal; squaring the absolute value; low pass filtering the squared result; computing the mean of the filtered signal; subtracting the mean from the filtered result; padding the mean subtracted result with zeros to form a value that is a power of two if the result is not already a power of two; computing a DFFT of the power of two result; normalizing the DFFT result of the last step; computing a mean of the normalization; computing a variance of the normalization; computing a power ratio of the normalization; classifying the mean, variance and power ratio as speech or non-speech based on how this feature vector compares to similarly constructed feature vectors of known speech and non-speech. The voice activity detector includes an absolute value squarer; a low pass filter; a mean subtractor; a zero padder; a DFFT; a normalizer; and a classifier.

US Patent:

20130035688, Feb 7, 2013

Filed:

Sep 25, 2012

Appl. No.:

13/626499

Inventors:

TYCO HEALTHCARE GROUP LP - Mansfield MA, US
Jeffrey R. Townsend - Loveland CO, US
Terrence R. Young - Erie CO, US

Assignee:

TYCO HEALTHCARE GROUP LP - Mansfield MA

International Classification:

A61B 18/14
B26D 3/00

US Classification:

606 48, 83 39

Abstract:

A bipolar forceps includes a shaft extending from a housing and includes an end effector assembly at its distal end. The end effector assembly has a pair of jaw members movable between an open position and a closed position. A knife assembly includes a cutter having a generally circular cross-section. The cutter is configured to cut tissue when the jaw members are in the closed position. One or more electrically conductive tissue sealing plates are disposed on each of the jaw members. The tissue sealing plates are adapted to connect to an electrosurgical energy source configured to deliver electrosurgical energy to tissue held between the jaw members to effect a tissue seal. An actuator is operably coupled to the knife assembly and is configured to selectively reciprocate the cutter relative to the jaw members.

US Patent:

55488331, Aug 20, 1996

Filed:

Jun 3, 1994

Appl. No.:

8/253378

Inventors:

Jeffrey A. Townsend - North Chelmsford MA

Assignee:

TranSwitch Corporation - Shelton CT

International Classification:

H04B 106
H03G 320

US Classification:

4552341

Abstract:

A data independent AGC control circuit for telecommunication applications is provided and includes an AGC amplifier, a fixed gain amplifier, a capacitor, and first, second, and third control circuits. The AGC amplifier has a data input, a control input, and a data output. The capacitor is coupled to the control input, and the charge on the capacitor effectively controls the gain of the AGC amplifier. The first control circuit is coupled to the data output of the fixed gain amplifier and to the capacitor and increases the stored charge on the capacitor when the data output exceeds a desired peak voltage level. The second control circuit is similarly coupled between the data output of the fixed gain amplifier and the capacitor, and decreases the stored charge on the capacitor when the data output exceeds a threshold voltage (typically 1/2 the desired peak voltage level). The third control circuit is coupled to the second control circuit and to the capacitor, and decreases the charge on the capacitor after the data output falls below the threshold voltage for a predetermined length of time. With the provided circuit, data values of zero will not trigger either the first or second control circuit, and the capacitor voltage and hence control voltage to the AGC amplifier will not change.