Digital signal noise filtering device

Abstract

The invention provides a digital signal noise filtering device comprising a first counting circuit for counting high-level input signals, a second counting circuit for counting low-level input signals and a RS trigger with an S end which is connected with the output of the first counting circuit and a R end which is connected with the output of the second counting circuit. As the first counting circuit and the second counting circuit do not respond to continuous false positive pulses and false negative pulses respectively, the RS trigger still outputs low level in spite of the emergence of the false positive pulses and still outputs high level in spite of the emergence of the false negative pulses after the outputs of the two counters are treated by the SR trigger; in such a way, when thedigital signal noise filtering device is used for blanking and filtering output signals of a power supply detection circuit, the digital signal noise filtering device can effectively filter the continuous false positive pulses and the false negative pulses, and the misoperation during the false power up or the false power off of a power supply can be avoided at the same time.

Description

technical field [0001] The invention relates to noise filtering and limiting technology, in particular to a digital signal noise filtering device. Background technique [0002] With the development of integrated circuits, more and more signal generation circuits, detection circuits and terminal receiving circuits are integrated into the chip to reduce costs. Due to the improvement of integration, the distance between the components and the wiring in the chip is getting smaller and smaller, so that the coupling between the signal and the signal, the signal and the power ground becomes non-negligible; The on-chip circuit that judges the off-chip signal cannot give the correct signal due to the influence of off-chip noise. It is precisely because of the aforementioned coupling and the existence of off-chip noise that it is inevitable that noise components will be introduced into the input signal of the receiving circuit of the terminal, thereby causing misoperation. Therefore...

AI Technical Summary

Problems solved by technology

Although the blanking circuit can filter both false positive pulses and false negative pulses of the input signal 10, and there is almost no delay between the output and the input, whether the rising edge or the falling edge of the input signal 10 itself is a real jump It becomes impossible to judge, for example, when the input signal 10 is "0", but at a certain moment due to noise, the input signal 10 undergoes a series of "0" and "1" flips, and then returns to "0", if these If the flipped width is less than the set filter delay, then the output 26 should remain "0" unchanged, but the output of this circuit will inevitably flip, resulting in misoperation

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