Patent ID: 8103234
Filing Date: 2012-01-24
Classification: H03G,H03M,H04B

Abstract:
1. A method of operating a radio receiver having an analog portion coupled to an A/D converter, and the A/D converter coupled to a digital signal processing portion, the digital signal processing portion using digital filtering to generate a narrow-band signal from a wideband signal received from the A/D converter and to recover data from the narrow-band signal, the method comprising: obtaining a wideband signal power estimate of total signal power reaching the A/D converter by measuring a digital signal between the A/D converter and the digital signal processing portion; comparing the wideband signal power estimate to a wideband signal power threshold; and responsive to comparing the wideband signal power estimate to a wideband signal power threshold, preventing the total signal power reaching the A/D converter from exceeding a maximum allowable input amplitude and, wherein preventing the total signal power reaching the A/D converter from exceeding a maximum allowable input amplitude comprises determining that the wide-band signal power estimate is greater than a predetermined first threshold, and, responsive thereto, reducing the gain of at least one amplifier coupled to an input terminal of the A/D converter, wherein the A/D converter is a sigma-delta A/D converter that includes a decimation and filtering processing chain and the wideband signal power estimate is obtained by taking a signal from an intermediate point in the decimation and filtering processing chain.