| 摘要 |
A polyphase quadrature digital tuner system which converts input signals to baseband inphase and quadrature signal components. The system includes a signal receiver which receives the input signals having a frequency centered around a predetermined carrier frequency. A signal processor continuously samples the input signals and multiplies selected portions of the input signals by a value of 1 or -1 to produce discrete sequences of N input samples, where N is an integer. An inphase signal channel includes a first set of N filters in a first filter stage each having respective filter coefficients, the first set of filters arranged to receive the discrete sequences, and a first signal summer which sums the outputs of the first set of N filters to produce the inphase signal component. A quadrature signal channel includes a second set of N filters in the first filter stage each having respective filter coefficients, the second set of filters arranged to receive the discrete sequences, and a second signal summer which sums the outputs of the second set of N filters to produce the quadrature signal component. The input samples are provided to the inphase and quadrature signal channels so that each filter of both channels receives one input sample of each sequence.
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