| 摘要 |
PURPOSE:To attain mobile radio communication via a control and speech channel in the pi/4 QPSK modulation wave delay detection demodulation system without using a frequency control means correcting a frequency error. CONSTITUTION:A Q base band signal obtained by multiplying an input signal with that via a pi/4 phase shifter 5 after the input signal is delayed by one symbol is used for a demodulation data on a control channel and a signal from a pi/2 phase shifter 4 is used for data demodulation on a speech channel by the changeover of a changeover switch 10 so as to expand the operating limit of a conventional temperature compensation crystal oscillator. |
