Speakerphone
Granted: August 12, 1997
Patent Number:
D382266
Remote interactive projector
Granted: October 22, 1996
Patent Number:
5568279
The projector of the present invention provides a means for interactively displaying and annotating a document image at two separate locations. The projector consists of an image plate having an array of picture elements for displaying the image; a projection mechanism for projecting the image displayed by the image plate onto a projection screen; and a digitizer having a coordinate input array which corresponds to the array of picture elements of the image plate, wherein the image…
Remote interactive projector
Granted: March 5, 1996
Patent Number:
D367663
Method and apparatus for periodic signal detection
Granted: February 14, 1995
Patent Number:
5390244
An apparatus and method for detecting the presence of ringer signals in a telephone which samples the incoming telephone signals within a prescribed time interval, windows the signals, and computes a set of auto-correlation coefficients. These coefficients are normalized, and their absolute values are calculated and summed and compared with an empirically-derived threshold. If the coefficient sum exceeds the threshold, a high degree of correlation within incoming signals is indicated,…
Method for fail-safe operation in a speaker phone system
Granted: November 15, 1994
Patent Number:
5365583
A method is disclosed for maintaining loop stability between a transmit and a receive path of a speaker phone which is capable of operating in either a full-duplex or a half-duplex mode. Loop stability is maintained and normal operation is achieved by controlling transmit and receive path attenuators. The method first determines whether feedforward or feedback signal levels should be used. Based on this determination, the signal and noise parameters along various points in the transmit…
Speaker phone
Granted: December 28, 1993
Patent Number:
D342732
