Adaptive equalizer for short distance metallic circuits

A circuit supplied with a receive signal received from an arbitrary one of a plurality of metallic lines, each having a varying loss characteristic with frequency, for automatically equalizing said signal to provide an equalized output signal having a substantially flat gain versus frequency characteristic over the frequency range of interest, said circuit comprising:

• an amplifier having inverting and noninverting inputs and an output, one of said inputs receiving said receive signal;
• and
• gain versus frequency responsive means including said amplifier and a resonant circuit for developing in response to said output a second signal having a gain versus frequency characteristic inversely proportional to that of said arbitrary one of a plurality of metallic lines and including means for supplying said second signal to said other one of said inputs of said amplifier.

A circuit for automatically equalizing an input signal selectively suppliable by an one of a plurality of metallic lines of varying loss characteristics, said circuit comprising:

• an amplifier means having first and second input terminals and supplied with said input signals at said first terminal and producing an output signal;
• and
• means for automatically adjusting the gain of said amplifier to inversely match the loss in gain with frequency produced by the selected metallic line, said means including a parallel resonance circuit connected to said second input terminal and to said output signal, said resonance circuit having a resonant frequency set above the operating frequency range over said metallic lines.

A circuit for adaptively equalizing an input received data signal, said signal being selectively suppliable by any one of a plurality of metallic lines of varying loss characteristics with frequency, said circuit comprising:

• amplifying means having a feedback path, said amplifying means accepting said input received data signal and providing an equalized output signal;
• and
• adjusting means connected in said feedback path for adaptively adjusting the output of said amplifying means to effectively compensate for the distortion introduced by the selected metallic line, said adjusting means further providing a feedback signal as a function of said equalized output signal and including variable impedance means responsive to said equalized output signal for providing said feedback signal and resonant circuit means having a fixed resonant frequency and being coupled between the output and the input of said amplifying means.