Have a look here for the Yokogawa FG420: Cost an arm and a leg, but video gives you an idea what to look for.
https://www.youtube.com/watch?v=lYBL-h4ssso
Now here is the cheap solution for DIY, just one arduino DUE and some included software to download.
https://www.hackster.io/BruceEvans/a...nerator-a9d180
Works perfect :-)
Tom
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