关键词：
.Design of Hybrid
hybrid filter
analog filters
摘要：
This paper presents design algorithms for hybrid filter banks (HFB's) for high speed, high-resolution conversion between analog and digital signals, The HFB is gn unconventional class of filter bank that employs both analog and digital filters, When used in conjunction with in array of slower speed converters, the HFB improves the speed and resolution of the conversion compared with the standard time-interleaved array conversion technique, The analog and digital filters in the HFB must be designed so that they adequately isolate the channels and do not introduce reconstruction errors that limit the resolution of the system, To design continuous-time analog filters for HFB's, a discrete-time-to-continuous-time ("Z-to-S") transform is developed to convert a perfect reconstruction (PR) discrete-time filter bank into a near-PR HFB;a computationally efficient algorithm based on the fast Fourier transform (FFT) is developed to design the digital filters abs HFB's. A two-channel HFB is designed with sixth-order continuous-time analog filters and length 64 FIR digital filters that yield -86 dB average aliasing error. To design discrete-time analog filters (e.g., switched-capacitors or charge-coupled devices) for HFB's, a lossless factorization of a PR discrete-time filter bank is used so that reconstruction error is not affected by filter coefficient quantization, A gaits normalization technique is developed to maximize the dynamic range in the finite-precision implementation. A four-channel HFB is designed with 9-bit (integer) filter coefficients. With internal precision limited to the equivalent of 15 bits, the maximum aliasing error is -70 dB, and with the equivalent of 20 bits internal precision, maximum aliasing is -100 dB, The 9-bit filter coefficients degrade the stopband attenuation (compared with unquantized coefficients) by less than 3 dB.
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中文科技期刊
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