Title:
OPTICAL RADIO TRANSMITTER
Document Type and Number:
Japanese Patent JP3535726
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent a communication opposite party from erroneously receiving data at searching, to reduce the drive current of a light-emitting element and to prolong operation time by means of battery drive by using a transmission circuit which lowers the drive current at transmission stand-by than that at transmitting of a signal, when the light-emitting element is searched.
SOLUTION: In a transmission circuit 10 of an optical radio transmission device, current I1 at the time of transmitting the signal of LED 1 is driven by the sine wave I1=IA+IBsinω>0 of amplitude IB(IB>0) with IA(>0) as a center. During searching, an input signal (f) is set to L, and the drive current (search current) I3 of LED 1 is set to 0<I3≤(IA-IB) and I3=IA-k2. Since a current value I3 at the time of searching is lower than the current value IA of a former case, the gate source voltage of a transistor Q1 becomes lower than the former case, and forward transmission admittance (gm) of the transistor Q1 also becomes lower.
Inventors:
Nakamura, Masato
Sakai, Yasutoshi
Nagashima, Motoyasu
Oka, Shigefumi
Sakai, Yasutoshi
Nagashima, Motoyasu
Oka, Shigefumi
Application Number:
JP2502798A
Publication Date:
June 07, 2004
Filing Date:
January 22, 1998
Export Citation:
Assignee:
VICTOR CO OF JAPAN LTD
NTT DATA CORP
NTT DATA CORP
International Classes:
G06F3/00; H04B10/11; H04B10/114; H04B10/40; H04B10/50; H04B10/564; H04B10/60; (IPC1-7): H04B10/04; H04B10/06; H04B10/10; H04B10/105; H04B10/14; H04B10/22; H04B10/26; H04B10/28
Attorney, Agent or Firm:
二瓶 正敬