From time to time it'd be really handy to have an oscilloscope. Something
like a Tektronix TDS2010 would be very nice. Too nice, and expensive,
for as often as I'd use it. And, much too good for the sorts of things
I'm likely to measure. An example would be watching for power supply
sags during computer boot-up, or maybe disk spin-up. Basically audio
bandwidth, but with the ability to capture transients by stop trigger.

What about "oscilloscopes" based on USB sound cards? The one that's
handy is xoscope, available via apt on RasPiOS. It's installed, but
the man page gives no hint what sort of sound device, or general purpose
A/D converters, are supported.

I don't have a hard-and-fast performance requirement, nor one for price.
It'd need to work from below 60Hz upwards, and cost around $10/kHz or
less at higher bandwidths with a cap in the $200-500 range. DC response
would be nice but not essential, calibrated amplitudes aren't really
necessary but would be convenient. Possibly the biggest constraint is
that I do not own a Windows license and have no modern Windows-compatible
hardware, so the choices are MacOS 10.7.5, RasPiOS or FreeBSD only.

If anybody has experiences or suggestions for devices and software to
consider please post.

Thanks for reading,

bob prohaska