Leaky digital integrator

An adaptive leaky integrator circuit comprising:

• adder means having first and second input terminals and operative to add digital signals input thereto to develop a summation signal;
• switching means having third and fourth input terminals and operative to periodically couple each of said third and fourth input terminals to said first input terminal;
• output terminal means;
• signal delay means for delaying said summation signal and for coupling the delayed summation signal to said second input terminal and to said output terminal means;
• and
• signal monitoring means for monitoring the signal level at said output terminal means and for determining whether or not the level of said delayed summation signal is above or below a predetermined reference level, for developing a decay signal commensurate therewith and for coupling said decay signal to said fourth input terminal so that it may be input by said switching means to said adder means wherein said delayed summation signal approximates the integral of update signals applied to said third input terminal modified by a slight decay factor as determined by said decay signal.

In an equalizer means having a plurality of taps, means for correlating the taps with an input signal and for developing tap update signals commensurate therewith, and leaky integrator means for integrating each of said update signals and for developing tap coefficient signals for modifying the output of the equalizer, an improved leaky integrator circuit comprising:

• accumulator means for accumulating update signals and for developing a tap coefficient signal;
• means for alternately and periodically coupling said update signals into said accumulator means and for similarly coupling one of a plurality of predetermined decay signals into said accumulator means so as to cause said tap coefficient to decay toward a predetermined reference value;
• and
• means for monitoring said tap coefficient signal, for determining which of said plurality of predetermined decay signals is to be developed, and for developing the particular decay signal to be input to accumulator means.