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:
Jul. 23, 1985
Filed:
Mar. 18, 1980
Akira Ashida, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
This invention relates to a clock deriving system as described below. At a base radio station, data is converted to a Manchester code and modulated into an FM, PM or AM radio wave. This radio wave is received by the antenna of a radio receiving apparatus and amplified and demodulated by a radio receiver of the apparatus into the base band signal of the Manchester code form. This signal is amplified and sliced by a limiter amplifier and then supplied to a clock derivation circuit where a useful clock component is derived. This clock component is passed through a filter of a necessary clock frequency band, from which clock information is produced. This clock information is applied to a phase detector where the output clock signal from a digital PLL and the input clock information are compared in phase, that is, detection is made of whether the former is ahead of or behind the latter. If the former signal is ahead of the latter, the phase detector produces '1', whereas if the former is behind the latter, the detector produces '0'. As a result, the digital PLL adjusts the phase of the incorporated clock oscillator therein, thereby deriving the clock signal of the input data.