Patent ID: 8270544
Filing Date: 2012-09-18
Classification: H04L

Abstract:
1. A system comprising: an antenna to receive radio frequency (RF) signals including incoming weather band radio signals; an analog front end to receive the incoming weather band radio signals from the antenna, the analog front end including: an analog mixer to mix the incoming weather band radio signals with a controllable oscillator frequency to generate a complex downmixed signal; and an analog-to-digital converter (ADC) to convert the complex downmixed signal to a digital signal; a digital signal processor (DSP) coupled to the analog front end, wherein the DSP includes: a first demodulator to demodulate the digital signal to generate a first demodulated signal; a second demodulator to receive the first demodulated signal and to obtain weather band data therefrom, wherein the second demodulator includes: an interpolator to receive samples of multiple frames of a message and generate soft decisions therefrom; a combiner to combine the soft decisions of the multiple frames into a hard decision corresponding to a bit of the weather band data; a preamble correlator to determine receipt of a preamble of the weather band data; and a timing controller to control a sampling rate of the interpolator under control of the preamble correlator, wherein the timing controller includes: a timing error detector coupled to an output of the interpolator to control the sampling rate to be at a maximum eye opening position; and a loop filter coupled to the timing error detector having a variable gain controlled responsive to determination of receipt of the preamble, wherein a gain of the loop filter is greater in an acquisition mode than in a tracking mode.