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. 30, 1990
Filed:
Aug. 22, 1988
Man Design Co., Ltd., Tokyo, JP;
Abstract
An FSK shift keying device includes a detector for detecting a transmission frame consisting of a preamble, data, and a postamble, a leading edge detector for detecting a leading edge of a voltage signal detected by the detector, a microprocessor for receiving a detection signal output from the leading edge detector as an interrupt signal, and resetting and restarting a timer, the timer for counting a time lapse in accordance with a clock signal from a clock generator, a sample and hold circuit for holding the voltage signal output from the detector when the time lapse counted by the timer reaches a duration of the preamble, a reference voltage generator for generating a reference voltage signal having an amplitude value which is 1/2 an amplitude value of the voltage signal from the detector, and a comparator for comparing the reference voltage signal with the voltage signal from the sample and hold circuit.