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:
Aug. 05, 1986
Filed:
Jun. 13, 1983
Dominique Godard, Le Rouret, FR;
Emile Morlec, Saint-Paul, FR;
International Business Machines Corp., Armonk, NY (US);
Abstract
The purpose of the receiver is to indicate the reception of a multifrequency signal and to identify said signal. A multifrequency signal is a signal combining two predetermined pure tones, one belonging to a high-frequency range, the other to a low-frequency range. The received signal is sampled at 8 KHz and digitally converted. The signal provided by the converter is simultaneously processed by two tone detectors. Each tone detector comprises: a bandpass filter covering the high- or low-frequency range and supplying the components (x, y) of the filtered signal in Cartesian coordinates; decimation means at the output of said filters; a converter converting the Cartesian coordinates (x, y) into polar coordinates (.rho., .theta.); and logic circuits analyzing the variations of said .rho. and .theta. over fixed periods of time to derive therefrom an identification of the received tone.