Analog gain control adjustment using a probabilistic algorithm

摘要

A method and apparatus (20) for adjusting the amplitude of a received discrete multi-tone analog signal (22) contaminated by radio frequency interference from radio stations in the AM band are described. The amplitude is adjusted by controlling an analog gain controller (32) in order to utilize substantially all of a dynamic input range of an analog-to-digital converter (ADC) (34) to reduce quantization noise of the output digital signal (40). A received signal monitor (36) extracts predetermined characteristics related to an amplitude distribution of a digital signal output by the ADC. An embedded processor module (38) calculates an amplification factor applied by the analog gain controller using the characteristics of the digital signal in a probabilistic algorithm, in order to adjust an amplitude of the analog signal to utilise a greater input dynamic range of the ADC, thereby reducing quantization noise of the output digital signal. Data discrimination is improved and the capacity of usable discrete multi-tone channels is increased. <IMAGE>