MODEM HAVING PHASE CORRECTOR AND VOLTAGE CONTROLLED OSCILLATOR EXECUTED BY USING MULTI-STAGE RING OSCILLATOR

摘要

PROBLEM TO BE SOLVED: To provide a carrier generation circuit used in MODEM by providing VCO containing an N-stage ring oscillator and providing a phase corrector generating a sum vector and a difference vector among balance vectors. ;SOLUTION: VCO 110 generates two balanced signals 111 (V1, V1B, V2 and V2B) and supplies them to the phase corrector 112. The first balance signal contains the vectors V1 and V1B and the second balance signal contains the vectors V2 and V2B. The phase corrector 112 receives the balance signals and generates a sum vector I carrier signal component 114 and a difference vector Q carrier signal component 116 by using the advantage of the principle of vector algebra. The balance signals 111 have equal sizes and have arbitrary phase differences, the balance vectors are appropriately connected, and the generated sum vector I and the differential vector Q are in the relation of a right angle. The sum/difference vectors I (in-phase) and the difference vector Q (quadrature-phase) carrier signal components are modulated for transmitting a data signal and are demodulated for receiving it.;COPYRIGHT: (C)1996,JPO