Pacific Microsonics, Inc.

Microsoft Technology Licensing, LLC

Sun Microsystems, Inc.

Michael W Pflaumer

Keith O Johnson

An analog-to-digital converter responsive to an analog signal converts the analog signal to a digital signal. A digital decimation filter, having an associated frequency response, is responsive to the digital signal for producing a decimated digital signal. An alias correction filter attenuates the decimated digital signal to remove distortion. A digital interpolation filter, having an associated frequency response, is responsive to the alias-corrected signal for producing an interpolated digital signal which subsequently is converted to an analog signal by a digital-to-analog converter. The alias correction filter has a frequency response that attenuates the decimated digital signal in a frequency range generally corresponding to a distortion portion that is present within the combination of the digital decimation filter frequency response and the digital interpolation filter frequency response.

Filter for digital-to-analog converters

An electronic method and apparatus for signal encoding and decoding to provide ultra low distortion reproduction of analog signals, while remaining compatible with industry standardized signal playback apparatus not incorporating the decoding features of the invention, and wherein the improved system provides an interplay of gain, slew rate and wave synthesis operations to reduce signal distortions and improve apparent resolution, all under the control of concealed control codes for triggering appropriate decoding signal reconstruction compensation complementing the signal analysis made during encoding. In addition, signals lacking the encoding process features of the invention are likewise compatible with playback decoders which do embody the invention, to provide some overall restoration enhancement.

Signal encode/decode system

Systems for enhancing frequency bandwidth

Hidden side code channels

Systems for achieving enhanced amplitude resolution

Systems for achieving enhanced frequency resolution

Silent data conversion system with sampling during electrical silence

Compatible signal encode/decode system

A local area network is disclosed including apparatus and methods for transmitting data between a plurality of data processing resources (agents) coupled to a cable. An agent desiring to send data to a receiving agent transmits a request to send (RTS) data packet which includes a control character requesting to either high or low speed data communication. Utilizing the teachings of the present invention, absent other predefined conditions a transmitting agent capable of high speed communication requests a high speed data exchange with the receiving agent. The RTS data packet itself is transmitted at low speed. Upon receiving the RTS packet, the receiving agent must transmit a clear to send (CTS) packet to the transmitting agent within a predetermined time after the receipt of the RTS packet. The CTS packet also includes a control character which either confirms that the data exchange will take place at high speed, or alternatively, a control character which requires a transmitting agent to use the low speed data rate. The transmitting agent, upon receipt of the CTS packet, generates and transmits a data packet to the receiving agent at either a high speed or low speed, depending upon the value of the control character with the CTS packet. The present invention further includes a status table maintained by each agent for tracking the address and communication capability of other agents coupled to the cable.

Variable speed local area network

Growing community of inventors

Berkeley, CA, United States of America

Michael W Pflaumer