An analog signal gain control circuit(ASGC) for a digital radio HomePlug
orthogonal frequency division multiplexing (OFDM) receiver includes a
digital variable gain amplifier (DVGA) to control the gain of a received
signal to achieve a desired signal amplitude to match a dynamic range of
an analog-to-digital converter (ADC), an inverse scaling stage controlled
to inverse-scale the signal output by the ADC, and a two-stage fast
attack and slow decay filter that outputs control signals to the DVGA and
to the inverse scaling stage. The fast attack and slow decay filter
rapidly responds to an increase in signal amplitude and slowly decays the
amplitude of the control signal in response to a decrease in input signal
amplitude.