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:
Feb. 11, 2003
Filed:
Jan. 09, 2002
Lars Risbo, Copenhagen, DK;
Texas Instruments Denmark A/S, Aalborg, US;
Abstract
In a digital amplifier of the PCM-UPWM type there is no negative feedback stage, which means that noise caused by the switching output stage of such an amplifier directly affects the audio signal. A regulation loop is inserted between the output and the input of the digital amplifier, the regulation loop being adapted to form a compensation signal c(k) which is multiplied by the audio signal to compensate noise and errors from the switching output stage. In an embodiment, the regulation loop consists of a multiplying D/A converter ( ) which is adapted to multiply the compensation signal c(k) by a multiplicative error signal m(t), and a summation unit ( ), by summation of the output of the multiplying D/A converter ( ) and a reference voltage ( ), forms a second error signal e(t) which is fed to a low-pass filter ( ) that is fed to the input of an ADC circuit ( ) to form the multiplicative error signal c(k), which, optionally via a second adaptation filter ( ), is fed to a multiplier ( ) and the multiplying D/A converter ( ). Expediently, the circuit of the invention is formed in full or in part by an integrated circuit.