Apparatus for filtering a signal utilizing recursion and decimation
First Claim
1. A digital signal filter bank device for filtering an external input signal to generate a filtered digital output signal, the device comprising:
- an input signal selector to select between the external input signal and a low-pass filtered feedback signal to provide a filter input signal;
a filter bank to receive the filter input signal and to filter the filter input signal to concurrently generate both a high-pass filtered signal and a low-pass filtered signal, wherein the low-pass filtered signal includes a low-pass filtered output signal and the low-pass filtered feedback signal; and
a frequency band selector to receive both the high-pass filtered signal and the low-pass filtered output signal directly from the filter bank to generate the filtered digital output signal;
wherein the filter bank includes a logic circuit to apply a distributed arithmetic algorithm to the filter input signal to generate first and second summations of product terms respectively representing the high-pass filtered signal and the low-pass filtered signal; and
wherein the filter bank further includes a low-pass filter to generate the low-pass filtered feedback signal using a decimated sampling rate.
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Abstract
Digital filter bank device that operates in a frequency-time hierarchically arranged, recursively fed back scheme based on the concept of decimation of a multi-speed-rate-operated system. The digital filter bank device operates in accordance with the computational requirement of summation of products for generating a filter output signal, and the computations are performed according to a software scheme based on a distributed arithmetic algorithm. The use of minimum hardware is enabled by a time-multiplexed scheme for both the implementation of the decimation and the distributed arithmetic principles of signal processing. The use of such a digital filter bank device results in a digital filter hardware architecture that has a significantly reduced semiconductor device die surface area.
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Citations
25 Claims
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1. A digital signal filter bank device for filtering an external input signal to generate a filtered digital output signal, the device comprising:
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an input signal selector to select between the external input signal and a low-pass filtered feedback signal to provide a filter input signal; a filter bank to receive the filter input signal and to filter the filter input signal to concurrently generate both a high-pass filtered signal and a low-pass filtered signal, wherein the low-pass filtered signal includes a low-pass filtered output signal and the low-pass filtered feedback signal; and a frequency band selector to receive both the high-pass filtered signal and the low-pass filtered output signal directly from the filter bank to generate the filtered digital output signal; wherein the filter bank includes a logic circuit to apply a distributed arithmetic algorithm to the filter input signal to generate first and second summations of product terms respectively representing the high-pass filtered signal and the low-pass filtered signal; and wherein the filter bank further includes a low-pass filter to generate the low-pass filtered feedback signal using a decimated sampling rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification