The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 05, 2010
Filed:
Apr. 29, 2005
Lars Risbo, Købernhavn Ø, DK;
Luis E. Ossa, Plano, TX (US);
Lars Risbo, Købernhavn Ø, DK;
Luis E. Ossa, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A digital audio system including a digital audio amplifier with reduced AM interference. The digital audio amplifier includes a pulse-width-modulation (PWM) processor in which a digital datastream is upsampled by an interpolation filter. A sample rate converter resamples the upsampled datastream to produce a datastream at a converted sampling frequency, or PWM frame rate. The converted datastream is then applied to pulse-width-modulation circuitry which generates a PWM signal at the PWM frame rate. The sample rate converter resamples according to a sample rate conversion ratio associated with the AM tuned frequency. For example, the sample rate conversion ratio can be selected so that the PWM frame rate and its lower harmonics avoid an AM tuned frequency, any intermediate frequency in the AM tuner, and also an image frequency in the tuner.