Transmitting power control unit having a constant output level throughout a predetermined frequency band

A transmitting power control unit comprising:

• a voltage controlled oscillator (VCO) for generating a transmission signal in accordance with a control voltage signal, an oscillating frequency of said VCO having a substantially linear relationship to said control voltage signal in a predetermined frequency band;
• a phase-lock loop (PLL) circuit, receiving said transmission signal, for (i) detecting a phase difference between said transmission signal and a reference signal indicative of channel information, (ii) generating said control voltage signal, and (iii) supplying said control voltage signal to said VCO so as to control the oscillating frequency of said VCO;
• a fixed voltage generator for generating a fixed voltage signal to designate a power level of the transmission signal in accordance with power control information;
• an adding circuit for generating an added voltage signal by adding said control voltage signal and said fixed voltage signal to each other;
• a power control circuit for controlling the power level of said transmission signal in accordance with said added voltage signal and outputting said transmission signal;
• and
• a filter, having a substantially linear frequency characteristic in said predetermined frequency band, for limiting a frequency band of the transmission signal outputted from said power control circuit.