| 摘要 |
In order to protect against adjacent channel interference and the effects of weak signal in AM signal processing, pre- and post-AM demodulation filters ( 36 and 38 ) may be used where the bandwidth of both is varied in the same manner by a single controlling mechanism ( 34 ). In one embodiment, two or more cascaded filters ( 20, 24 or 22, 26 or 30,32 ) may be used for the pre- and post-demodulation filters where each of the cascaded filters has a same predetermined order and uses the same set of coefficients. In one embodiment, all cascaded filters are first order IIR filters, which reduces computation complexity. The use of a same set of coefficient for all the cascaded filters results in a same bandwidth for all filters and further reduces computation complexity. In an alternate embodiment, cascaded filters may be used for only one of the pre- and post-demodulator filters.
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