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:
Nov. 23, 1999
Filed:
Oct. 22, 1997
David Stanley McGrath, Bondi, AU;
Lake DSP Pty Limited, New South Wales, AU;
Abstract
A method of processing audio input signals comprising 1-bit, Sigma-Delta Modulated (SDM) signals is disclosed including the steps of combining the audio input signals to form a combined audio input signal; and utilising a Sigma-Delta Modulator to convert the combined audio input signal to a corresponding Sigma-Delta Modulated output signal. The method can include a linear mix of the audio input signals and each audio input signal can multiplied by a corresponding gain factor before being added together with other of the audio input signals. The Sigma-Delta Modulator can include a noise shaping filter designed to amplify components of the audio input signals below a predetermined threshold frequency and the combining step can include utilising a negative feedback of the combined audio input signal. The noise shaping filter can utilise a series of integrating circuits as a means to decrease the sensitivity of the filter to errors in its coefficients.