Automatic equalizer for analog channels having means for comparing two test pulses, one pulse traversing the transmission channel and equalizer

Claim 1

APPARATUS FOR ESTABLISHING OPTIMUM SETTINGS FOR THE ATTENUATORS IN A TRANSVERSAL EQUALIZER INTENDED FOR THE CORRECTION OF THE FREQUENCY RESPONSE CHARACTERISTIC OF A BAND-LIMITED TRANSMISSION MEDIUM COMPRISING MEANS AT ONE END OF SAID TRANSMISSION MEDIUM TRANSMITTING A FIRST SERIES OF TEST PULSES THROUGH SAID MEDIUM AND SAID EQUALIZER, MEANS AT THE OTHER END OF SAID TRANSMISSION MEDIUM GENERATING A SECOND SERIES OF TEST PULSES IN SYNCHRONISM WITH SAID FIRST SERIES, A REFERENCE FILTER HAVING THE FREQUENCY RESPONSE CHARACTERISTIC DESIRED FOR SAID TRANSMISSION MEDIUM IN TANDEM WITH SAID GENERATING MEANS, MEANS DERIVING AN ERROR SIGNAL FROM A COMPARISON OF SAID FIRST AND SECOND SERIES OF TEST PULSES, MEANS CORRELATING SAID ERROR SIGNAL WITH THE INPUTS TO THE INDIVIDUAL ATTENUATORS OF SAID EQUAILIZER OVER THE INTERPULSE PERIOD, MEANS DETERMINING THE POLARITY OF THE OUTPUTS OF SAID CORRELATING MEANS, AND MEANS RESPONSIVE TO SAID DETERMINING MEANS ADJUSTING THE SETTINGS OF SAID ATTENUATORS INCREMENTALLY IN A DIRECTION OPPOSITE TO SAID POLARITY.