Synthesis of Subband Hybrid Filter Banks ADCs with finite word-length coefficients using adaptive equalization

Abstract

Subband Hybrid Filter Banks (SHFB) ADCs are able to convert one or several narrow subbands among a given wideband signal. That provides an appropriate solution to "flexible spectrum" management for cognitive radio applications. In this paper, a SHFB ADC delivering a complex signal is considered. The optimal values of the digital coefficients are obtained thanks to an adaptive equalization method. The impact of digital coefficients quantization to the SHFB is studied. For a reconstruction quality target, the minimum quantization step is determined. This is validated in time and frequency domain with simulation results.

Hybrid Filterbank ADCs With Blind Filterbank Estimation

“…We have presented numerical experiments showing the improved performance of the blind estimation method, and the clear advantage of the proposed LMS design. (13) and (9), we have that Now, (21) follows from (10) and the following property: Also, (22) follows from (12) and (20), and (23) follows from (12), (19) and (20 where . In this case, for a given , we can find by solving (41) for , provided the matrix has full row rank.…”

“…An approach to deal with this uncertainty is to use a reference input signal to estimate the analog filterbank parameters [9]. A similar approach is used in [10]- [12], where instead of estimating the analog filterbank, the digital synthesis bank is directly tuned, via an adaptive filtering technique, to minimize the reconstruction error. However, as pointed out in [13], a blind estimation technique (i.e., one carrying out the estimation without the knowledge of the input signal) is preferred, since it does not interfere with the ADC operation, and is able to track analog parameter drifts during the ADC operation.…”