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:
Apr. 27, 2004
Filed:
May. 15, 2001
Applicant:
Inventors:
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka-fu, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04B 1/004 ;
U.S. Cl.
CPC ...
H04B 1/004 ;
Abstract
A digital electrical signal Vin for transmission is supplied to a transistor Q , a current compensation circuit , and a signal current source to be band-compensated for generating a signal current I . A predetermined current Id for a constant-current source is subtracted from the signal current I , and the result is an injection current Iin that drives an LED . The current Id is adjusted so that the injection current Iin becomes 0 at the low level. Thus, a signal-to-noise (S/N) ratio in waveform of light outputted from the LED can be improved. Accordingly, the S/N ratio of the transmitted signal can be improved with band compensation.