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:
Jun. 04, 2002
Filed:
May. 29, 1998
John M. Burgan, N. Palm Beach, FL (US);
James H. Carlquist, Austin, TX (US);
John R. Oakley, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A digital tone generator ( ) includes a digital signal generator ( ) which generates a digital waveform data sequence which is representative of a tone having a predetermined waveform, and a pulse-width modulator ( ) which provides an adaptive duty cycle period ( ) which is responsive to the digital data waveform data sequence for selecting clock pulses of a number sufficient to generate a pulse-width modulated digital tone signal. The digital tone generator ( ) can also include a low pass filter ( ) which processes the pulse-width modulated digital tone signal to generate an analog tone signal. The digital waveform sequences generated by two digital tone generators ( ) can be digitally added by a digital adder ( ) to provide a composite tone data signal, which can be processed by the adaptive pulse-width modulator ( ) to produce a pulse-width modulated tone signal representative of a DTMF tone.