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:
May. 05, 2015
Filed:
Feb. 14, 2011
Hiroshi Koizumi, Kanagawa, JP;
Kazuyoshi Nishimura, Kanagawa, JP;
Masafumi Nogawa, Kanagawa, JP;
Yoshikazu Urabe, Kanagawa, JP;
Hiroshi Koizumi, Kanagawa, JP;
Kazuyoshi Nishimura, Kanagawa, JP;
Masafumi Nogawa, Kanagawa, JP;
Yoshikazu Urabe, Kanagawa, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
NTT Electronics Corporation, Kanagawa, JP;
Abstract
A comparator () outputs, out of an electrical signal input from a trans impedance amplifier (TIA) via a coupling capacitor, pulses having amplitudes equal to or larger than a reference value as a comparison output signal (Cout). An analog holding circuit () charges a holding capacitor with each pulse contained in the comparison output signal (Cout) and also removes a DC voltage obtained by the charging via a discharging resistor, thereby generating a holding output signal (Hout) that changes in accordance with the presence/absence of input of an optical signal. This allows to perform an autonomous operation without any necessity of an external control signal and properly detect the presence/absence of input of an optical signal.