A digital processing method of the minimum shift keying (MSK) excitation signal is proposed for cascaded power amplifiers with phase shift control. Through the mathematical characteristics of MSK signal, the frequency extraction of MSK excitation signal and the accurate judgment of code conversion time are realized by Analog-to-digital converter (ADC). To avoid the accumulation of errors in frequency detection, a comparator is used at the beginning of each cycle to calibrate the inverter output signal and MSK excitation signal. Compared with traditional analog method, the proposed method is realized by ADC, which has the advantages of simple structure, high precision, and high waveform reduction Simulation models of digital and analog extraction method are constructed, indicating that the method has the advantages of accurately judging the code conversion time and extracting the frequency. The method can realize the digital processing of MSK signal and generate the control signal of cascaded power amplifiers with phase shift control.

Cascade power amplifier, digital processing method, MSK, phase shift control