US 2007/0176660 A1 · Systems and Methods for Pulse Width Modulating Asymmetric Signal Levels

Abstract

Systems and methods for pulse width modulating waveforms to represent asymmetric signal levels using pulses that are symmetric within their respective switching periods. One embodiment comprises a pulse width modulation system including an asymmetric correction unit and a pair of modulators. The asymmetric correction unit receives samples of an input signal and produces two separate output signals for corresponding modulators. For each sample, the asymmetric correction unit determines whether the signal level of the sample is symmetric or asymmetric. If the signal level of the sample is symmetric, the sample is forwarded to each of the modulators. If the signal level is asymmetric, the asymmetric correction unit increases one modified sample to the next higher symmetric signal level and decreases another modified sample to the next lower symmetric signal level and forwards the modified samples to the modulators.

Claims20

Dependent claims

A pulse width modulation system comprising:

an asymmetric correction unit;
a first modulator coupled to the asymmetric correction unit;
a second modulator coupled to the asymmetric correction unit;
wherein the asymmetric correction unit is configured to receive samples of an input signal;
and
wherein for each sample, the asymmetric correction unit is configured to
determine whether a signal level of each sample is one of a set of symmetric signal levels or one of a set of asymmetric signal levels,
when the signal level of the sample is one of the symmetric signal levels, forward the sample to each of the modulators, and
when the signal level of the sample is one of the asymmetric signal levels, forward a first modified sample to the first modulator and a second modified sample to the second modulator, wherein the signal level of one of the modified samples is increased by a selected amount to one of the symmetric signal levels and the signal level of the other of the modified samples is decreased by the selected amount to one of the symmetric signal levels.

6 more elements

Dependencies are inferred from the claim text.

Systems and Methods for Pulse Width Modulating Asymmetric Signal Levels

Life of this patent

Systems and Methods for Pulse Width Modulating Asymmetric Signal Levels

Life of this patent

Abstract

Claims20