| 主权项 |
1. A receiving apparatus for demodulating a received signal obtained by receiving a wireless transmission wave which is modulated according to a series of data sequences including frames each having a synchronization signal, the receiving apparatus comprising:
a frequency converting part for performing a frequency conversion on the received signal and obtaining a frequency converted signal including a baseband signal, a filter for eliminating high frequency noise components from the frequency converted signal and obtaining a high frequency noise eliminated signal, a frequency detector for performing a frequency detection on the high frequency noise eliminated signal and obtaining a frequency detection signal, a frequency offset detector for detecting a frequency offset occurring in the frequency converted signal on the basis of the frequency detection signal, a frequency correction part for sifting frequency of the frequency converted signal by the amount of the frequency offset, a synchronization detector for detecting the presence of the synchronization signal in each of said frames, and generating a synchronization detection signal which has a first level as far as the synchronization signal is not detected and has a second level when and after the synchronization signal is detected; and a passband setting part for setting an upper limit of frequency of a passband in the filter at a lower frequency within a time period in which the synchronization detection signal is kept at the second level than that within a time period in which the synchronization detection signal is kept at the first level. |
