Automatic cable equalizer

Claim 2

Apparatus for equalizing the pulse response of a data transmission cable comprising: an active filter, responsive to said cable''s output signal, exhibiting a transfer frequency response characterized by an adjustable gain factor and by a transmission zero in the frequency domain at an adjustable frequency; detection means responsive to the output signal of said active filter for generating a control signal responsive to the peak signal level of said active filter''s output signal; means responsive to said control signal for adjusting said gain of said active filter to maintain a constant active filter peak output signal; and means responsive to said control signal for adjusting said frequency of said transmission zero of said active filter in accordance with a fixed linear relationship between said frequency and the inverse of said gain.

Claim 3

Apparatus for equalizing applied digital signals prior to regeneration of said digital signals comprising: an equalizer responsive to said applied digital signals for optimizing the decision region for said regeneration of said applied digital signals, said equalizer exhibiting a frequency response comprising a factor k(1 + s/g), where k is a controllable gain factor of said equalizer, g is a controllable constant which specifies the zero frequency location, and s is the complex frequency variable; and means responsive to said equalizer''s output signal for adjustably increasing said zero frequency location specifying constant, g, and for adjustably decreasing said gain factor, k, with respect to an increasing peak signal level of said equalizer''s output signal in accordance with a k-g relationship that is subsumed by a preselected eye opening region common to a selected range of cable temperatures, cable lengths, and cable gauges.

Claim 4

Apparatus for equalizing applied digital signals prior to regeneration of said digital signals comprising: an equalizer responsive to said applied digital signals for optimizing the decision region for said regeneration of said applied digital signals, said equalizer exhibiting a frequency response comprising a factor k(1 + s/g), where k is a controllable gain factor of said equalizer, g is a controllable constant which specifies the zero frequency location, and s is the complex frequency variable; and means responsive to said equalizer''s output signal for adjustably increasing said zero frequency location specifying constant, g, and for adjustably decreasing said gain factor, k, with respect to an increasing peak signal level of said equalizer''s output signal in accordance with a k-g relationship that is subsumed by a preselected eye opening region common to a selected range of cable temperatures, cable lengths, and cable gauges.

Claim 5

The apparatus defined in claim 2 wherein said subsumed k-g relationship is 1/k K1g + K2 where K1 and K2 are fixed constants.

Claim 6

The apparatus defined in claim 2 wherein said k-g relationship subsuming a preselected common eye opening is k K1g + K2 where K1 and K2 are fixed constants.

Claim 7

The apparatus defined in claim 2 wherein said means for adjusting the values of k and g further comprise: means responsive to the peak voltage output signal of said equalizer for developing a control signal Vc; means responsive to said control signal, Vc, for monotonically altering said frequency specifying constant, g, in response to an increasing control signal, Vc; and means responsive to said control signal, Vc for varying said gain factor, k, in accordance with the relation 1/k K1g + K2 where K1 and K2 are predetermined constants.

Claim 8

Apparatus for improving the signal response of a cable including equalizer means, having an adjustable signal amplitude response factor and adjustable frequency response transmission zero factor, for processing said cable output signal, comprising: means responsive to said equalizer output signal for detecting the peak signal value of said equalizer output signal; means responsive to said detecting means output signal for varying the amplitude response factor of said equalizer in accordance with said detected peak output signal value to maintain a constant peak output signal value; and means responsive to said detecting means output signal for varying the frequency response transmission zero factor of said equalizer in accordance with said detected peak output signal value to maintain a linear relation between the inverse of said amplitude response factor and said frequency response factor.

Claim 9

Apparatus for improving the signal response of a cable including equalizer means, having an adjustable signal amplitude response factor and adjustable frequency response transmission zero factor, for processing said cable output signal, comprising: means responsive to said equalizer output signal for detecting the peak signal value of said equalizer output signal; means responsive to said detecting means output signal for varying the amplitude response factor of said equalizer in accordance with said detected peak output signal value to maintain a constant peak output signal value; and means responsive to said detecting means output signal for varying the frequency response transmission zero factor of said equalizer in accordance with said detected peak output signal value to maintain a linear relation between the inverse of said amplitude response factor and said frequency response factor.

Claim 10

Apparatus for improving the digital signal response of a cable including a biquadratic active filter, responsive to an output signal of said cable, said filter exhibiting a frequency response including a gain factor, k, and a transmission zero, g, in the frequency domain, and having a first resistor which controls solely the gain of said filter, in an inverse manner, and a second resistor which controls solely the frequency of said transmission zero of said filter, in a direct manner, wherein the improvement comprises: means responsive to the peak signal value of said output signal of said filter for monotonically and jointly varying the values of said first and second resistors in response to said peak signal value.

Claim 11

Apparatus for improving the digital signal response of a cable including a biquadratic active filter, responsive to an output signal of said cable, said filter exhibiting a frequency response including a gain factor, k, and a transmission zero, g, in the frequency domain, and having a first resistor which controls solely the gain of said filter, in an inverse manner, and a second resistor which controls solely the frequency of said transmission zero of said filter, in a direct manner, wherein the improvement comprises: means responsive to the peak signal value of said output signal of said filter for monotonically and jointly varying the values of said first and second resistors in response to said peak signal value.

Claim 12

The apparatus defined in claim 7 wherein said first resistor affecting said gain, k, and said second resistor affecting said transmission zero, g, are varied in accordance with the relation 1/k K1g + K2 where K1 and K2 are preselected constants.

Claim 13

Apparatus for equalizing the pulse response of a data transmission cable comprising: an active filter, responsive to said cable''s output signal, exhibiting a transfer frequency response characterized by an adjustable gain, k, factor and by a transmission zero factor, g, adjustable in the frequency domain; detection means responsive to the output signal of said active filter for generating a control signal, Vc, responsive to the peak signal level of said active filter''s output signal; means responsive to said control signal for adjusting said gain, k, of said active filter to maintain a constant peak output signal of said active filter; and means responsive to said control signal for adjusting said zero, g, of said active filter in accordance with a fixed linear relationship proportional to said gain.

Claim 14

Apparatus for equalizing the pulse response of a data transmission cable comprising: an active filter, responsive to said cable''s output signal, exhibiting a transfer frequency response characterized by an adjustable gain, k, factor and by a transmission zero factor, g, adjustable in the frequency domain; detection means responsive to the output signal of said active filter for generating a control signal, Vc, responsive to the peak signal level of said active filter''s output signal; means responsive to said control signal for adjusting said gain, k, of said active filter to maintain a constant peak output signal of said active filter; and means responsive to said control signal for adjusting said zero, g, of said active filter in accordance with a fixed linear relationship proportional to said gain.

Claim 15

The apparatus defined in claim 9 wherein said means for adjusting the values of k and g further comprises: means responsive to said control signal, Vc, for monotomically altering said frequency specifying constant, g, in response to an increasing control signal, Vc; and means responsive to said control signal, Vc, for varying said gain factor, k, in accordance with the relation k K1g + K2 where K1 and K2 are predetermined constants.