Hi Will, Given that you already have an FPGA in the system I'll assume that you are comfortable with digital solutions. Have a look at https://www.analog.com/en/products/ad7402.html ; it's a 1-bit sigma-delta modulator with a built-in galvanic isolation for its output. TI and ST have similar parts (for some you need to add your own isolator); we've used them in power quality analysis experiments. By having the modulator on the primary side you can use a simple resistor divider, saving you from possible group delay issues.
Good luck and let us know how it goes, JDB. [Disclaimer: I don't have my notes here to double check whether we ended up using the AD7402 or a similar part; do double check the isolation offered to see whether this particular chip suffices for your mains voltage safety requirements] On Sat, Jan 22, 2022 at 1:55 AM willl will <[email protected]> wrote: > Hi everyone, > > I have an recently finished project that also measuring AC waveform, full > description here: > https://github.com/will127534/RaspberryPiAtomicNixieClock/wiki > > Basically using an AC transformer and Ti's ADC8681 @ 50Khz sampling rate. > > This year I'm working on a earthquake sensor + AC mains monitor system (In > an earthquake prone area, AC mains frequency will fluctuate by power > generator and machine emergency stop like this one: > https://twitter.com/kuriuzu/status/1360602496821911553). > > I want to improve AC measurement. Apart from the ADC sampling speed upgrade > (previously bottlenecked by the SPI connection to FPGA). I'm currently > debating about whether or not to bypass the transformer. How does the > distortion of an AC transformer impact the accuracy of mains waveform and > frequency? I'm not sure if it is worth it to go through the mains voltage > safety requirements. > > Thanks, > Will > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send > an email to [email protected] > To unsubscribe, go to and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
