Automatic equalization system

摘要

An automatic equalization system includes an analog-to-digital converter (3) for periodically sampling an analog signal representative of digital information in response to a sampling clock signal, and for converting every sample of the analog signal into a corresponding digital sample to convert the analog signal into a corresponding digital signal. A first device (6) operates for detecting a phase error of the sampling clock signal in response to a correlation between samples of the digital signal generated by the analog-to-digital converter. A second device (15,16,7) operates for controlling a frequency of the sampling clock signal in response to the phase error detected by the first device. A variable filter (4) operates for subjecting the digital signal generated by the analog-to-digital converter to a variable filtering process to convert the digital signal generated by the analog-to-digital converter into a filtering-resultant signal. The filtering process corresponds to a waveform equalization process. A third device (8) operates for detecting an amplitude error of the digital signal generated by the analog-to-digital converter in response to a correlation between samples of the filtering-resultant signal generated by the variable filter. A fourth device (8) operates for controlling the filtering process implemented by the variable filter in response to the amplitude error detected by the third device. The analog-to-digital converter, the first device, and the second device compose a phase locked loop while the variable filter, the third device, and the fourth device compose an amplitude error correcting loop separate from the phase locked loop.