Making a microcontroller perform as a frequency counter is a fairly simple task including the measurement of the time period during which a number of pulses are counted. The maximum frequency is nevertheless restricted to a fraction of the microcontroller’s clock speed as well as the accuracy of the resulting instrument depends on that of the clock crystal so it will barely result in the very best of frequency counters. It’s something [FrankBuss] has approached with an Arduino-based counter that offloads the timing concern to a hold PC, as well as therefore declares atomic accuracy because of its clock being connected to a master source via NTP. The Rust code PC-side provides constant readings whose accuracy boosts the longer it is left counting the source. The example shown reaches 20 parts per billion after a number of hours reading a 1 MHz source.
It’s remove that this is barely the most practical of frequency counters, nevertheless we can see that it might discover a utilize for anyone intent on tracking the long-lasting stability of a source, as well as might even be utilized with some type of comments to self-control an RF source against the NTP clock with the utilize of an appropriate prescaler. Its true calling may come though not in measurement however in calibration of one more instrument which can be changed to match its reading when it has settled down. There’s surely no cheaper method to satisfy your inner frequency common nut.
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