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:
Jan. 29, 1991
Filed:
Nov. 02, 1989
Shahid U Qureshi, Natick, MA (US);
Fuyun Ling, Jamaica Plain, MA (US);
Codex Corporation, Mansfield, MA (US);
Abstract
A sample rate converter receives an input stream of samples representative of a time-varying signal and generates a corresponding output stream of samples which is also representative of the time-varying signal and in which each output stream sample appears at a desired time which may differ from the time when a sample appears in the input stream; filter circuitry receives the input stream and generates at least two intermediate samples which appear at different times, and interpolation circuitry combines selected intermediate samples to form a sample of the output stream at the desired time. In another aspect, an improvement is provided for a modem of the kind in which a line signal is sampled at times governed by an unstable clock to generate a first sample stream in which the samples appear with possibly changing sampling phases and a converter converts the first sample stream to a second stream of samples appearing at times that are possibly different from the times of appearance of the samples in the first sample stream; the improvement is means for providing to the converter signals representative of the changing phases of the samples in the first sample stream to cause the conversion to occur in a manner that reduces the contribution of the changing sampling phases to the times of appearance of the samples in the second sample stream.