Cascaded digital filters with reduced latency
AssigneeKeysight Technologies, Inc.
InventorsDaniel Y. Abramovitch, Christopher R. Moon
Life of this patent
Estimating the term…
Abstract
A filter and method for filtering a signal are disclosed. The filter is equivalent to a plurality of bi-quad filters connected in series, and is implemented on a digital processor that receives a sequence of signal values at a sampling rate characterized by a sampling interval and generates a filtered signal value upon receiving each received signal value. The filter has a latency that is less than the sampling interval. The filtered values can be generated by adding a term to a received signal value and multiplying the sum by a gain constant that depends on the filter constants. The added term does not depend on the current received signal value. The filter can be implemented in fixed-point integer arithmetic.
Claims20
A filter comprising any positive integer number of poles and zeros where this filter is equivalent to a plurality of bi-quad and/or bilinear filters connected in series, said filter being implemented on a digital processor that receives a sequence of signal values at a sampling rate characterized by a sampling interval and generates a filtered signal value upon receiving each received signal value, said filter having a latency that is less than said sampling interval.
A method for filtering a signal to generate a filtered signal that approximates the results of filtering said signal through a series connected string of bi-quad or bilinear filters, said method comprising:
- receiving a sequence of signal values at a sampling rate characterized by a sampling interval;
- generating a filtered signal value corresponding to each received signal value by adding a term to said received signal value and scaling the result to provide said filtered signal value, said term being independent of said corresponding received signal value;
- outputting said filtered signal value;
- and
- generating said term corresponding to said next signal value prior to receiving said next signal value.
Dependencies are inferred from the claim text.