Abstract: An improved decision feedback phase lock loop having an erasure zone detector and a feedback loop interrupting switch responsive to the output of the erasure zone detector which cooperate to eliminate from the feedback loop those error signals corresponding to detected data falling within certain predetermined regions of the encoding constellation. The erasure zone detector compares the complex input signal to certain predetermined erasure zone reference signals so as to determine when the input signal falls within an erasure zone and correspondingly actuates the loop switch to prevent certain feedback error signals from being input to the loop filter.

Abstract: A complex ternary correlator and method for adaptive gradient computation in an adaptive equalizer and including four ternary operation circuits, four ternary multiplier circuits for obtaining the cross products of the ternary operation outputs, a subtractor circuit for developing a signal commensurate with the difference between two of the ternary multiplier outputs, an adder circuit for developing a signal commensurate with the sum of the remaining two ternary multiplier outputs and two identical integrating circuits for obtaining the real and imaginary adaptive tap coefficient update increments in an adaptive equalizer.

Abstract: V.29 constellation detection method and apparatus including a quadrant transformer for Processing the quantized real and imaginary component signals corresponding to a particular transmitted signal from a known set of transmitted signals by effectively rotating such components into first quadrant position while at the same time developing a quadrant designating signal or tag; a real part quantizer for determining within which of several real part regions the rotated real part component resides; a boundary line intersect selector for dynamically determining the imaginary part limits correspondence to the real part region selected; an imaginary part quantizer for determining within which of several imaginary part regions the rotated imaginary part component resides; and a constellation point selector which in response to the quantized real part, imaginary part information and quadrant information selects one of 16 constellation points as being the signal most likely received.