Bit stream frequency measuring device and method

Abstract

The invention discloses a bit stream frequency measuring device and method. According to the bit stream frequency measuring device and method, a timer interruption triggering unit generates timing interruption and acquires the electric level value of signals to be tested at a certain time point; and an electric level value reading unit actively reads the electric level value of an external frequency signal input pin and stores the electric level value in a bit stream buffer zone each time when interruption is executed; when the bit stream buffer zone is full, timer interruption is stopped; data analysis is performed on a bit stream, so that all rising edges and falling edges in the bit stream are identified; the coordinates of the first and last edge change are recorded, and the number ofsignal half cycles is calculated; and an interruption triggering count calculation module calculates interruption triggering counts averagely occupied by each signal half cycle, an interruption execution time calculation module calculates time for executing timer interruption one time, and a to-be-tested signal frequency calculation module calculates the frequency of the signals to be tested. Withthe bit stream frequency measuring device and method of the invention adopted, an actual frequency measurement upper limit can be extended to 3 times of a theoretical upper limit, and precision is ata millesimal level. The bit stream frequency measuring device and method are suitable for being applied to signal frequency measurement in a CPU.

Description

technical field [0001] The invention relates to the technical field of signal measurement, in particular to a bit stream frequency measurement device and method. Background technique [0002] The principle of bit stream is that a binary digital signal enters a module with a reference voltage, the input signal is higher than the reference voltage and the output is 1, otherwise it is 0; the second signal is compared with the first signal, and the higher one is output 1, lower output 0, and so on. Because it only compares the size between signals, the samples need to be increased, requiring a higher sampling frequency. Only one bit signal will enter a DAC called Switched Capacitor (Switched Capacitor) to restore it to an analog signal. [0003] At present, there are mainly equal-precision frequency measurement and interrupt-triggered frequency measurement (also known as edge capture) technologies in the field of signal frequency measurement. If the existing frequency measure...

AI Technical Summary

Problems solved by technology

If the existing frequency measurement needs ultra-high precision (million level), it needs CPU and FPGA to cooperate with processing, but if in order to save system cost or save structural space, due to the high cost of FPGA, there can only be one CPU, and Sometimes a non-real-time system (such as Android system) is running in the CPU. If the existing technology can theoretically measure a signal of 150KHz, but due to the influence of the non-real-time system, it can only measure a signal with a lower frequency (within 50KHz)

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