Patent ID: 6668032
Filing Date: 2003-12-23
Classification: H04L

Abstract:
A network receiver configured for receiving a modulated carrier signal representing a frame of data from another network transmitter via a network medium, the network receiver comprising:a) an analog to digital converter generating a sequence of digital samples representing the modulated carrier signal, the sequence of digital samples occurring at an A/D clock frequency; b) a frame detection circuit setting the A/D clock frequency to a first sampling frequency when a first modulation specification is detected and setting the sampling clock frequency to a second sampling frequency when the first modulation specification is not detected; and c) a receiver circuit recovering data from the digital samples and generating a frame type signal indicating the modulation specification, wherein the first modulation specification utilizes pulse position modulation of the carrier signal, a second modulation specification utilizes quadrature amplitude modulation of the carrier signal, and a third modulation specification utilizes a combination of pulse position modulation of the carrier signal and quadrature amplitude modulation of the carrier signal, the frame detection circuit includes a carrier sense circuit for detecting the duration of a power pulse in an envelope signal, and the frame detection circuit sets the A/D clock frequency to the first sampling frequency when the duration of a power pulse is less than a duration of a pulse position modulation power pulse and the frame type signal does not indicate the third frame type.