High pass filtering with automatic phase equalization
AssigneeCirrus Logic, Inc.
InventorsEric T. King, Douglas F. Pastorello
Life of this patent
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Abstract
A system and method for selectively providing high pass filtering of two digital signals that are to be subsequently combined. Each of the first and second signals is passed through one of a high pass filter, an all-pass filter and a module that performs substantially no signal filtering, where the phase and magnitude for either high pass filter are substantially equal to the phase and magnitude for either all-pass filter. At the minimum, the system provides the following filtering combinations for the respective first signal and second signal: (no filter, no filter), (high pass, high pass), (high pass, all-pass) and (all-pass, high-pass). Suitable first order high pass and corresponding all-pass filters are determined.
Claims14
Apparatus for providing selective high pass filtering of two associated digital signals, the apparatus comprising:
- a first signal processing module that receives a first digital signal and passes the first signal through a first filtering module, through a second filtering module or through a third filtering module, depending upon the value of a switching command, to produce a first filtered signal;
- a second signal processing module that receives a second digital signal and passes the second signal through a fourth filtering module, through a fifth filtering module or through a sixth filtering module, depending upon the value of the switching command, to produce a second filtered signal;
- and
- wherein the first and fourth filtering modules comprise substantially identical high pass filters, the second and fifth filter modules comprise substantially identical all-pass filters, and the third and sixth filtering modules provide no filtering of a signal, and wherein the first and second signals may be passed through the following pairs of filter modules:
- first and fourth filter modules, second and fourth filter modules, first and fifth filter modules, and third and sixth filter modules.
A method for providing selective high pass filtering of two associated digital signals, the method comprising:
- receiving a first digital signal and passing the first signal through a first filtering module, through a second filtering module or through a third filtering module, depending upon the value of a switching command, to produce a first filtered signal;
- receiving a second digital signal and passing the second signal through a fourth filtering module, through a fifth filtering module or through a sixth filtering module, depending upon the value of the switching command, to produce a second filtered signal;
- and
- providing the first and fourth filtering modules as substantially identical high pass filters, providing the second and fifth filter modules as substantially identical all-pass filters, and providing no filtering for a signal that passes through the third filtering module or the sixth filtering modules;
- and
- passing the first and second signals through one of the following pairs of filter modules:
- first and fourth filter modules, second and fourth filter modules, first and fifth filter modules, and third and sixth filter modules.
Dependencies are inferred from the claim text.