Title:
TRANSPONDER
Document Type and Number:
Japanese Patent JP3197966
Kind Code:
B2
Abstract:
PURPOSE: To conduct high-quality communication and at the same time execute simultaneous communication with plural receivers by adopting a spectrum diffusion communication method for a transponder.
CONSTITUTION: A question signal emitted from an antenna 4 is received at an antenna 5 on a tag B side and 180° phase-shift is carried out by means of a modulation circuit 6 and again the signal is delivered out to the antenna 4 on a transmitter side from the antenna 5. The responding signal received at the antenna 4 is inputted into recovery circuits 13a, 13b. Also, through a circulator 3, a question signal (f) is inputted into the recovery circuit 13a as it is, and a question signal (f) whose phase-shift is 90° advanced or retarded more than the basic question signal (f), is inputted into the recovery circuit 13b through a phase-shifter 14. A signal containing a PN sign outputted from one of the recovery circuits 13a, 13b is inputted into correlators 16a, 16b through band pass filters 15a, 15b. PN signs are inputted into the correlators 16a, 16b from PN sign generators 17a, 17b, and when correlation is obtained at each, a predetermined correlation value is obtained.
Inventors:
Kenji Nakata
Application Number:
JP34528992A
Publication Date:
August 13, 2001
Filing Date:
November 30, 1992
Export Citation:
Assignee:
Nippon Signal Co., Ltd.
International Classes:
B61L25/02; G01S13/75; G01S13/76; G01S13/79; H04B1/59; (IPC1-7): B61L25/02; G01S13/75; G01S13/76; G01S13/79; H04B1/59
Domestic Patent References:
| JP61211162A | ||||
| JP604340A | ||||
| JP592458A |
Attorney, Agent or Firm:
Mitsumasa Ishii