Adaptive inter-symbol interference boost equalization apparatus and method

An adaptive equalization apparatus for mitigating inter-symbol interference effects on digital data transferred by a transmit device on a parallel bus, said adaptive equalization apparatus comprising:

• a low-pass filter element receiving an input signal from said device and outputting a filtered signal, said low-pass filter element having an adjustable frequency boost gain input for adjusting a gain value of said low-pass filter element;
• a latching comparator being coupled to said low-pass filter element and receiving said filtered signal, said latching comparator comparing an amplitude of said filtered signal in a given high range of frequencies with a threshold voltage level corresponding to an amplitude of said filtered signal in a lower range of frequencies below the given high range of frequencies and outputting a comparison value;
• a digital counter being coupled to said latching comparator and receiving said comparison value, said digital counter outputting a counter value based on said comparison value,
• wherein said counter value is supplied to said adjustable gain input of said low-pass filter element to adaptively control the gain value of said low-pass filter element in order to adjust the amplitude of said filtered signal to said threshold voltage level.

A method for mitigating inter-symbol interference effects on an oscillating signal from which digital data will be obtained at a receive end of a channel, the inter-symbol interference being introduced into said oscillating signal as a result of transmitting said oscillating signal at a transmission frequency through the transmission channel over a substantial distance from a transmit device to the receive end of the channel, said method comprising:

• receiving, by a filter element, an input signal from said transmit device, said filter element having a mechanism for adjusting a boost gain for a given high range of frequencies within the predetermined frequency band;
• outputting, by said filtered element, a filtered signal;
• determining an amplitude difference value based on a comparison of a high frequency amplitude of said filtered signal in the given high range of frequencies compared to a low frequency amplitude of the filtered signal in a lower range of frequencies below the given high range of frequencies;
• and
• controlling adjustments to the boost gain, by a boost control mechanism, so that based on said amplitude difference value.

A method of mitigating inter-symbol interference effects on digital data transferred by a transmit device on a parallel bus, comprising:

• receiving, by a low-pass filter element, an input signal from said transmit device, said low-pass filter element having an adjustable gain input for adjusting a boost gain value of said low-pass filter element;
• outputting, by said low-pass filter, a filtered signal having a predetermined frequency band;
• initiating adaptive equalization of said input signal;
• detecting and storing as a threshold voltage level a low frequency voltage level corresponding to a low frequency amplitude of the filtered signal for a given low range of frequencies of the predetermined frequency band and storing it as a threshold voltage level;
• comparing a high frequency amplitude of said filtered signal, for a given high range of frequencies of the predetermined frequency band above the given low frequency range, with said threshold voltage level and outputting a comparison value;
• supplying said comparison value to a digital counter, said digital counter outputting a counter value based on said comparison value,
• wherein said counter value is supplied to said adjustable gain input of said low-pass filter element to adaptively control the gain value of said low-pass filter element in order to adjust the amplitude of said filtered signal to said threshold voltage level.