Continuous-time (CT) filters are widely used in signal processing but, owing to the large spread in the process parameters which determine their time constants, they require a tuning system to align their frequency characteristics. Several techniques have already been proposed in the literature and are commonly employed, but usually they require either a doubling of the filter circuitry or some complex self-calibration scheme, resulting in sensible area overhead or high computational complexity. Here, we present a novel tuning approach which can be applied to both master-slave and self-calibration arrangements and is based on the evaluation of a few samples of the input-output cross-correlation function of the filter, when the input signal is a finite length sequence of pseudorandom pulses. The key advantages of the proposed technique are basically the ease of generation of the input bit-stream and the simplicity of the circuitry required to sample the filter output and to perform the cross-correlation operation. As a consequence, the area overhead associated to the tuning circuitry is kept very small. Some simulation results of the application to the tuning of a low-Q telecommunication filter are given and an extension to the tuning of high-Q active filters is also explored in order to assess the effectiveness and robustness of the proposed technique.
Corsi, F., Matarrese, G., Marzocca, C., Dragone, A., Baschirotto, A., D'Amico, S. (2007). Tuning of High-Speed Telecommunication Filters, via I/O Cross-Correlation Evaluation. IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS. I, REGULAR PAPERS, 54(2), 329-337 [10.1109/TCSI.2006.886005].
Tuning of High-Speed Telecommunication Filters, via I/O Cross-Correlation Evaluation
BASCHIROTTO, ANDREA;
2007
Abstract
Continuous-time (CT) filters are widely used in signal processing but, owing to the large spread in the process parameters which determine their time constants, they require a tuning system to align their frequency characteristics. Several techniques have already been proposed in the literature and are commonly employed, but usually they require either a doubling of the filter circuitry or some complex self-calibration scheme, resulting in sensible area overhead or high computational complexity. Here, we present a novel tuning approach which can be applied to both master-slave and self-calibration arrangements and is based on the evaluation of a few samples of the input-output cross-correlation function of the filter, when the input signal is a finite length sequence of pseudorandom pulses. The key advantages of the proposed technique are basically the ease of generation of the input bit-stream and the simplicity of the circuitry required to sample the filter output and to perform the cross-correlation operation. As a consequence, the area overhead associated to the tuning circuitry is kept very small. Some simulation results of the application to the tuning of a low-Q telecommunication filter are given and an extension to the tuning of high-Q active filters is also explored in order to assess the effectiveness and robustness of the proposed technique.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.