| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a digital FSK receiver that can make more accurate demodulation even if interfusion of a disturbing wave having the same frequency as a frequency of a desired signal. <P>SOLUTION: The digital FSK receiver includes: a detecting portion 31 detecting a new signal on the basis of a received signal from which an ambient noise is filtered out by an adaptive filter 21, a prior-to-signal-detection power section 25a holding a first smoothed power Pb(t) that is a power of a signal received before a new signal is detected; a posterior-to-signal-detection power section 25b calculating a second smoothed power Pa(t) that is a power of a signal received after the new signal is detected; a comparator 25c comparing levels of the first and second smoothed powers; a selector 32 selecting the received signal from which the ambient noise is filtered out by an adaptive filter 21 when the first smoothed power is higher than the second smoothed power and selecting the received signal bypassing the adaptive filter 21 when the first smoothed power is lower than the second smoothed power; and a demodulating portion 33 demodulating a desired signal on the basis of the received signal selected by the selector 32. <P>COPYRIGHT: (C)2009,JPO&INPIT |
