| 摘要 |
A digital Zero-IF Selectivity Section (DZISS) (20, 20'). The DZISS of the present invention teaches a topology that facilitates realization in both transmitter (20') and receivers (20). In the preferred low-speed embodiment, the digital filters (32, 32', 33, 33') are comprised of cascaded filter sections (64a-64d) employing decimation (66) to reduce the data rate. In the preferred high-speed embodiment, the digital filters (32, 32', 33, 33') are more sophisticated as at least the first filter section (64') is decomposed to enable high-speed operation. Decimation (66) is also employed on the high-speed embodiment to allow subsequent circuitry to operate at a lower data rate thus consuming less power. In an alternate embodiment, applicable to the low-speed and high-speed preferred embodiments, sections of the digital low pass filters (100A, 100B) are time multiplexed (104) effectuating a cost and space savings. |
