Dynamic error quantizer tuning systems and methods
AssigneeMaxim Integrated Products, Inc.
InventorCharles Razzell
Life of this patent
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Abstract
Dynamic error-quantizer tuning systems and methods prevent misconvergence to local minima by using a dynamic quantizer circuit that controls reference voltages of three or more comparators that are independently adjusted to modify the transfer function of the dynamic quantizer circuit. A weighted sum of the comparator outputs is subtracted from the input to form an error signal in a control loop. The ratio of the reference voltages is chosen to reduce or eliminate local minima during a convergence of the control loop and is set to values that minimize a mean squared error signal with respect to discrete modulation states of the input after the convergence of the control loop is complete.
Claims11
A soft quantizer circuit comprising:
- a first differential pair amplifier;
- a second differential pair amplifier coupled to the first differential pair amplifier;
- and
- a third differential pair amplifier coupled to the second differential pair amplifier, the second and third differential pair amplifiers comprising differential base input terminals that are DC biased to substantially equal thresholds of opposite polarity to offset zero-crossing points of the second and third differential pair amplifiers relative to a nominally zero-crossing point of the first differential pair amplifier.
An error detection circuit comprising:
- a first differential pair amplifier;
- a second differential pair amplifier coupled to the first differential pair amplifier;
- and
- a third differential pair amplifier coupled to the second differential pair amplifier, the second and third differential pair amplifiers comprising differential base input terminals that are DC biased to substantially equal thresholds of opposite polarity to offset zero-crossing points of the second and third differential pair amplifiers relative to a nominally zero-crossing point of the first differential pair amplifier, the error detection circuit, in response to receiving an input signal, generates an error estimate proportional to a difference between an output signal and a quantized version of that output signal.
Dependencies are inferred from the claim text.