Digital audio receiver with reduced AM interference
US7809346B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 2005 |
| Grant date | Oct 5, 2010 |
| Priority date | — |
| Expiry date | Jun 25, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/217
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.