Transducer of signal input/output signal device having compensation contraction and enlargement A-D converter

Application Number: 00109008
Application Date: 2000.06.01
Publication Number: 1276658
Publication Date: 2000.12.13
Priority Information: 1999/6/2 JP 154853/1999
International: H04J13/02;H04Q7/38
Applicant(s) Name: NEC Corp.
Inventor(s) Name: Nomura Tomishige
Patent Agency Code: 11021
Patent Agent: zhu haibei
Abstract In a spread spectrum transmitter, a number of spread spectrum channel signals are multiplexed into a digital amplitude signal by a multiplexer and the time-average power of the digital amplitude signal is determined by an average calculator (3). The digital amplitude signal is interpolated by an interpolator (2), scaled according to a first scale factor by a bit shifter and converted to an analog amplitude signal by a D/A converter. The analog amplitude signal is then scaled by according to a second scale factor in a gain controlled amplifier. The first and second scale factors are complementarily varied by a control circuit (4) according to the output o the average calculator so that the carrier-to-noise ratio of the transmitter is maintained substantially constant regardless of the varying power level of the multiplexed signals.