Title:
CIRCUIT AND METHOD FOR CARRIER LEAK SUPPRESSION OF ORTHOGONAL PHASE MODULATOR
Document Type and Number:
Japanese Patent JP3022231
Kind Code:
B2
Abstract:
PURPOSE: To suppress a carrier leak by mixing an I-phase base-band signal with an I-phase offset and also mixing a Q-phase base-band signal with a Q- phase offset.
CONSTITUTION: A carrier leak suppressing circuit 306 includes a pseudo-noise generator 340 which has code length N. An I code signal 354 is generated by extracting a phase shifter 370 at a bit position 3 and a Q-phase code signal 352 is generated by extracting the phase shifter 370 at a bit position N-1. Signals 354 and 352 represent spectrum spread codes. Signals 352 and 354 are added to the I-phase base-band signal 342 and Q-phase base-band signal 344 so as to separate an I-phase and a Q-phase component. The signals 354 and 352 are generated by a generator 340 while having lower power levels than the signals 342 and 344 so as to evade interference with modulating operation performed by a Q-phase modulator 30.
Inventors:
James Russell Blodgett
Application Number:
JP1328895A
Publication Date:
March 15, 2000
Filing Date:
January 04, 1995
Export Citation:
Assignee:
AT&T CORP.
International Classes:
H03C1/52; H03C3/40; H03D7/16; H04L27/20; H04L27/36; (IPC1-7): H04L27/20; H04L27/36
Domestic Patent References:
| JP2148940A | ||||
| JP5130156A | ||||
| JP4267657A |
Attorney, Agent or Firm:
Hirofumi Mitsumata
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