azonenberg changed the topic of #scopehal to: libscopehal, libscopeprotocols, and glscopeclient development and testing |,, | Logs:
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<_whitenotifier-3> [scopehal-apps] azonenberg pushed 2 commits to master [+6/-4/±0]
<_whitenotifier-3> [scopehal-apps] azonenberg 0e5e5db - Moved fgtest/curvetrace to examples directory
<_whitenotifier-3> [scopehal-apps] azonenberg e9705ca - Initial version of freqresp example
<azonenberg> using the wavesurfer function generator to generate the signal then the waverunner to measure power before and after the DUT
<azonenberg> This approach eliminates the need to have a calibrated output level on the function generator (so you could for example use a cheap SDR as the signal source, which is what i plan to do for a 50 MHz - 2 GHz sweep tomorrow)
<azonenberg> you dont even need to know the scope's frequency response, it's entirely ratiometric and measures S21 directly
<azonenberg> all it relies on is the two scope channels being matched
<azonenberg> lain: ^
<azonenberg> Flat within measurement error (the spikes are i think one scope LSB high lol), if i averaged longer it would probably look nicer
<azonenberg> but for a quick and dirty test this is enough, i'll fine-tune once we have the faster signal source up
<azonenberg> The ~ -0.14 dB average S21 is mostly due to me using 1K ohm resistors, producing 21:1 attenuation
<azonenberg> but i couldn't find a good RF 950 ohm
<azonenberg> Easy to correct for in post, also i think it might be possible to tell the scope this is a 21x probe
<azonenberg> lecroy seems to be nice and flexible for this kind of stuff
<lain> :D
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