Timing recovery for an automatically equalized data modem

An apparatus for removing at least some of the distortion from an analog signal, said apparatus comprising:

• means for sampling the analog signal to provide a data signal having a digital format;
• an equalizer having a data signal path for the transmission of data through the equalizer and first means responsive to the data signal for providing a substantially equalized data signal at the output of the data signal path;
• said first means including a plurality of multiplier means each of which is capable of multiplying the data signal by an associated multiplying coefficient;
• means for varying the values of at least some of said multiplying coefficients;
• a timing control network;
• means for coupling the timing control network to at least one of the multiplier means through a timing signal path, said timing signal path being different from said data signal path,
• said timing control network including means for monitoring through said timing signal path a characteristic of the multiplying coefficient of said at least one multiplier means and means responsive to said characteristic for adjusting the sampling means;
• and
• phase correction means for substantially correcting the phase of at least one of the data signal and the equalized data signal substantially independently of the multiplying coefficients.

An apparatus adapted to receive a distorted analog signal comprising:

• first means for sampling the analog signal to provide a plurality of samples with adjacent samples being separated by a first interval of time, the samples being expressed in a digital format to form a distorted digital data signal;
• equalizer means including a plurality of taps, each of the taps having a multiplying coefficient with characteristics for substantially equalizing the distorted digital signal to provide a substantially equalized signal;
• second means responsive to the characteristics of the multiplying coefficient of at least one of the taps of the equalizer means to control the duration of the first interval of time;
• and
• phase correction means for correcting the phase of at least one of the data signal and the equalized signal substantially independently of the multiplying coefficients.

An apparatus for removing at least some of the distortion from a modulated analog signal, said apparatus comprising:

• means for sampling the modulated analog signal to provide a first signal having a digital format;
• means for demodulating the modulated signal to provide a demodulated signal and for providing components of the demodulated signal in first and second channels;
• equalizer means responsive to the demodulated signal to provide a substantially equalized signal;
• said equalizer means including a first and second plurality of multipliers in said first and second channels respectively, each of said multipliers having an associated multiplying coefficient and being capable of multiplying at least one of said components by such multiplying coefficient;
• means for controlling the values of at least some of said multiplying coefficients which are employed by said multipliers;
• timing control means responsive solely to the multiplying coefficient of at least one of said multipliers of said first plurality of multipliers for adjusting said sampling means;
• phase correction means responsive to a phase error signal or substantially correcting the phase of the equalized signal a substantially phase corrected signal;
• and
• means responsive to the substantially phase corrected signal and independent of the multiplying coefficients for providing said phase error signal.