Abstract: An embodiment is a method and apparatus to process an input signal. An analog automatic gain control (AGC) processor controls an analog adjustable gain of the input signal using a feedback mechanism. The analog AGC processor generates a first signal. A processing circuit transforms the first signal into a second signal. A digital AGC processor controls a digital adjustable gain of the second signal using a feed-forward mechanism.

Abstract: An embodiment is a method and apparatus to perform symbol synchronization. A correlation estimator computes a correlation of a sample vector representative of a narrowband signal. A synchronization detector detects symbol synchronization. Another embodiment is a method and apparatus to perform frame synchronization. A Fast Fourier Transform (FFT) processing unit computes a current FFT vector and an accumulated previous FFT vector. The current FFT vector and the accumulated previous FFT vector correspond to sample vectors associated with preamble symbols. A real and imaginary processing unit generates real and imaginary summations using the current FFT vector and the accumulated previous FFT vector. A mode processor generates mode flags representing operational modes using the real and imaginary summations.

Abstract: According to one embodiment of the invention, an integrated circuit comprises an encoding module, a modulation module and a spectral shaped module. The encoding module includes an interleaver that adapted to operate in a plurality of modes including a first mode and a second mode. The interleaver performs repetitive encoding when placed in the second mode. The modulation module is adapted to compensate for attenuations that are to be realized during propagation of a transmitted signal over the power line. The spectral shaped module is adapted to compensate for amplitude distortion and further compensates for attenuations that will be realized during propagation of the transmitted signal over the power line.

Abstract: An embodiment is a method and apparatus to estimate channel quality. An absolute processor computes absolute real and imaginary values of real and imaginary parts, respectively, of output of a demodulator. A phase count unit generates first and second phase counts representing deviations from zero phase noise using the absolute real and imaginary values. An amplitude count unit generates first and second amplitude counts representing attenuation of a received signal using the absolute real and imaginary values. An integrator integrates the first and second phase counts and first and second amplitude counts into a signal quality indicator that represents a measure of quality of channel with respect to noise and fading.