| 摘要 |
PURPOSE:To highly stably and highly accurately demodulate a signal at any time by providing a broad band constant phase shifting amplitude limiter, make the signal level of received data constant, and setting the delay quantity for one symbol with the use of the delay time difference between two band pass filters using surface acoustic wave element respectively. CONSTITUTION:A broad band constant phase shifting amplitude limiter 13 is provided between a band pass filter 3 of an input circuit part and a same phase hybrid transformer 5, and the amplitude level of the respective PSK modulated waves at different receiving levels arriving from plural slave stations with different transmission distance respectively is made constant. Further a delay line 20, to which the PSK demodulated signal branched to two by the same phase hybrid transformer 5, is composed of two band pass filters 21a and 21b using the surface acoustic wave elements and of a phase shifter 22 for phase fine adjustment, and the difference of the two delay quantities is set at a value for one symbol of the PSK demodulating signal. Thus the signal can be highly stably and highly accurately demodulated at any time. |
