Programmable glitch filter
AssigneeTexas Instruments Incorporated
InventorsKhodor S. Elnashar, Jay T. Cantrell, Clarence D. Lewis
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Abstract
A glitch filter identifies and eliminates positive edge and negative edge glitches without utilizing a high frequency sampling clock. The glitch filter comprises a programmable delay buffer string, two multiple input AND gates and a latch. The buffer string provides a plurality of incrementally delayed signals and utilizes them as signal samples thus simulating a high frequency sampling clock. The two multiple input AND gates serve to eliminate positive or negative edge glitches. The latch outputs the accurate filtered data without any positive or negative edge glitches.
Claims11
A glitch filter for a singal, comprising:
- a delay circuit, having an input coupled to the signal, and having a plurality of outputs wherein the delay circuit comprises:
- a plurality of programmable delay buffers each with an input and an output connected together in series such that they form a string, wherein the signal is connected to the input of the first delay buffer in the string and the output of each buffer in the string forms the plurality of outputs and wherein the plurality of outputs of the delay circuit provide an incrementally sampled signal without the use of a high frequency clock;
- and
- filtering means connected to the plurality of outputs of the delay circuit.
A method of filtering noise without the use of high frequency sampling circuitry, comprising the steps of:
- sending a signal through a plurality of programmable delay buffers coupled together in series, wherein an output of each buffer forms a plurality of incrementally delayed signals;
- and
- filtering the plurality of incrementally delayed signals by treating each incrementally delayed signal as an instantaneous digital signal wherein the plurality of incrementally delayed signals act as an equivalent high frequency sampling mechanism.
Dependencies are inferred from the claim text.