Offset calibration system and method for a high gain signal channel
AssigneeAnalog Devices, Inc.
InventorsAidan J. Cahalane, Simon Atkinson
Life of this patent
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Abstract
A direct current offset correction system is disclosed for use in an analog signal processing system. The offset correction system includes a comparator unit for comparing the polarity of signals from an analog signal channel and producing a binary output signal. The system also includes a digital accumulator unit that is coupled to the comparator output signal for providing an accumulated average signal over a predetermined period of time. The system also includes a threshold corrective signal unit for determining whether the accumulated signal is within a defined threshold window of acceptable values. The system further includes a correction unit for applying a corrective signal to the analog signal channel.
Claims28
A direct current offset correction system for use in an analog signal processing system, said offset correction system comprising:
- comparator means for comparing polarity of signals from an analog signal channel and producing a binary output signal;
- digital accumulator means coupled to said comparator output signal and to a first clock signal for providing an accumulated average signal over a predetermined period of time;
- threshold corrective signal means for determining whether said accumulated signal is within a defined threshold window of acceptable values;
- and
- correction means coupled to said threshold corrective signal means for applying a corrective current to said analog signal channel.
A direct current offset correction system for use in an analog signal processing system, said offset correction system comprising:
- comparator means for comparing polarity of signals from an analog signal channel and producing a comparator binary output signal;
- accumulator means coupled to said comparator output signal and to a first clock signal for providing an accumulated avenge signal over a predetermined period of time;
- reset means for resetting the accumulator means;
- and
- correction means coupled to said accumulator means for applying a corrective signal to said analog signal channel.
A direct current offset correction system for use in an analog signal processing system, said offset correction system comprising;
- comparator means for comparing polarity of signals from an analog signal channel and producing a comparator output signal;
- accumulator means coupled to said comparator output signal for providing an accumulated average signal over a predetermined period of time responsive to a clock signal from a first clock;
- threshold corrective signal means coupled to a second clock signal that is relatively slow compared to said fast clock signal, said threshold corrective signal means for determining whether said accumulated signal is within a defined threshold window of acceptable values;
- and
- correction means coupled to said threshold corrective signal means for applying a corrective signal to said analog signal channel.
A method of correcting for direct current offset in an analog signal processing system, said method comprising the steps of:
- a) receiving analog signals in an analog signal channel
- b) comparing each of said analog signals with a reference to determine whether a direct current offset exists and producing a comparator output signal;
- c) providing a first clock signal at a first frequency;
- d) accumulating a sum of comparator output signals over a predetermined period of time to determine an accumulated value;
- and
- e) applying a correction signal to the analog signal channel responsive to whether said accumulated value is outside of a window threshold.
Dependencies are inferred from the claim text.