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:
Mar. 07, 1989
Filed:
Mar. 05, 1987
Kouzou Kage, Tokyo, JP;
Yoshiharu Tamura, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A noise detection circuit for a digital radio receiver comprises a sampling circuit for sampling a digital baseband signal having a noise component when an eye opening of the baseband signal is largest. A waveform generator is connected to the output of the sampling circuit for generating a waveform which is a replica of the baseband signal and free from the noise component. The waveform generator comprises a threshold comparator having decision thresholds and a waveform recovery circuit which includes a resistor, a plurality of storage capacitors of equal values and a switch responsive to the output of the threshold comparator for selectively coupling the output of the sampling circuit through the resistor to the storage capacitors. A substractor is connected to the outputs of the sampling circuit and the waveform generator for generating a signal representative of the noise component of the baseband signal. The output of the subtractor circuit can be used for various purposes including noise measurement, squelch action and automatic local oscillator frequency control.