Fast learn digital adaptive equalizer

Apparatus adapted for use as an equalizer comprising:

• first means for connection to a communication channel said first means including a plurality of taps settable for compensating for distortion in said channel;
• and
• second means for producing a plurality of successive samples of signals representing in-phase and quadrature-phase components of the impulse response of said channel and for operating upon said samples to form elements of a matrix equation from said samples, to iteratively calculate the exact values of the optimum settings for said taps utilizing said elements, and to set said taps to said optimum values, wherein said samples are both auto-correlated and cross-correlated and wherein said matrix equation includes complex constants and complex variables.

Apparatus adapted for use as an equalizer comprising:

• a first means for connecting to a communication channel, said first means including a plurality of taps settable for compensating for distortions in said channel;
• and
• second means for producing a plurality of successive samples of first and second signals representing the impulse response of said channel and for operating upon said samples to form elements of a matrix equation from said samples, to iteratively calculate the exact values of the optimum settings for said taps utilizing said elements, and to set said taps to said optimum values, wherein said successive samples are derived from a received test impulse and wherein said exact values are calculated in a time less than the duration of said received test impulse.

In an equalizer supplied with a training waveform including a carrier-only signal, and including means for sampling said training waveform, apparatus for detecting the carrier-only signal comprising:

• means for providing a succession of arc tangents from the samples derived during said carrier-only signal;
• and
• means for testing said arc tangents to determine that a carrier-only signal is present.

The equalization apparatus comprising:

• means for receiving signals transmitted across a distorting medium and having a plurality of tap coefficients settable for compensating for distortion in said signals induced by said medium;
• means responsive to a training signal containing therein the response of said medium to only one transmitted impulse for sampling said response to produce a plurality of impulse response samples;
• means operative upon said impulse response samples to auto-correlate and cross-correlate said samples, form elements of a matrix equation from the auto-correlated and cross-correlated samples, said elements including complex constants and complex variables, said variables defining the optimum initial settings for said tap coefficients, for iteratively calculating the exact values of said optimum initial settings utilizing said constants, and for setting said tap coefficients to said exact values to substantially remove said distortion.

In combination with an equalizer means adapted to receive a first signal transmitted across a distorting medium, said equalizer means having a plurality of taps settable for compensating for distortion in said first signal induced by said medium, the apparatus comprising:

• means for generating a plurality of second signals representing samples of in-phase and quadrature-phase impulse response signals, said impulse response representing that of said distorting medium;
• and
• means operative upon said second signals to auto-correlate and cross-correlate said second signals, form elements of a matrix equation from the auto-correlated and cross-correlated said second signals, said elements including complex constants and complex variables, said variables defining the optimum initial settings for said taps, for iteratively calculating the exact values of said optimum initial settings utilizing said constants in N iterations for an N.times.N matrix and for setting said taps to said exact values to produce a substantially distortion free signal.

In combination with an equalizer means adapted to receive a first signal transmitted across a distorting medium, said equalizer means having a plurality of taps settable for compensating for distortion in said first signal induced by said medium, the apparatus comprising:

• means for generating a plurality of second signals representing samples of in-phase and quadrature-phase impulse response signals, said impulse response representing that of said distorting medium;
• and
• means operative upon said second signals to auto-correlate and cross-correlate said second signals, form elements of a matrix equation from the auto-correlated and cross-correlated said second signals, said elements including complex constants and complex variables, said variables defining the optimum initial settings for said taps, for iteratively and nonconvergently calculating the exact values of said optimum initial settings utilizing said constants and for setting said taps to said exact values to produce a substantially distortion free signal.