Patent ID: 8810307
Filing Date: 2014-08-19
Classification: H03H

Abstract:
1. Apparatus for tuning a Gm-C filter, comprising: a Gm-C filter including one or several interconnected Gm-C cells, the Gm-C cells having a transconductance amplifier, a tuning terminal, and a transconductance gain (gm) that is dependent from an electric value present on the tuning terminal; the Gm-C filter including one or more switching elements, allowing to configure the Gm-C filter in a calibration configuration and in a filtering configuration; a digital controller, operatively arranged to measure a response of the Gm-C filter in the calibration configuration, and to generate a digital tuning value depending on the response measured; a digital-to-analogue converter, converting said digital tuning value into an analogue tuning signal, fed to the tuning terminals of the Gm-C cells; and an amplitude regulation unit operatively arranged to limit the forward gain when the Gm-C filter is in the calibration configuration; wherein the apparatus is operatively arranged to converge, in the calibration configuration, to a predefined response, and the digital-to-analogue converter is operatively arranged to maintain the resulting tuning signal in the filtering configuration.