| 摘要 |
In a spread spectrum transmitter, a number of spread spectrum channel signals are multiplexed into a digital amplitude signal by a multiplexer (1) 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 (5) and converted to an analog amplitude signal by a D/A converter (6). The analog amplitude signal is then scaled by according to a second scale factor in a gain controlled amplifier (7). The first and second scale factors are complementarily varied by a control circuit (4) according to the output o the average calculator (3) so that the carrier-to-noise ratio of the transmitter is maintained substantially constant regardless of the varying power level of the multiplexed signals. <IMAGE> |
