04-03-2018, 07:43 AM
(This post was last modified: 04-03-2018, 07:45 AM by Diabolical Artificer.)
Agreed you need something better than an average soundcard to get -100dB but some cheap cards like the Creative Soundblaster (horrible name) can do -96dB. I use a second hand AI, a Digidesign 002 THD + N 96dB - specs here - http://avid.force.com/pkb/articles/en_US...e/en365819 . It cost £50. I've only started mucking about with some of this software recently. So far I've had good results, there are also quite a few knowledgable folks out there who also use these to measure audio parameters. It's good enough I think for hobbyists and dabblers like myself who can't afford AP stuff or older HP audio analysers.
Nick doesn't say what level of THD he's after, but this simple Wein bridge oscillator is capable of about 0.03% THD. See attached. It's set for 1khz, to change frequency change R and associated caps. i have some bulbs Nick, if you want some to play with, drop us a line.
From the little I know designing and building a very low distortion analogue sig source is far from simple, even at just one frequency. i have the Elektor Spot frequency schematics and other very low THD designs and white papers if you want them Nick, but they're not simple.
Andy.
Nick doesn't say what level of THD he's after, but this simple Wein bridge oscillator is capable of about 0.03% THD. See attached. It's set for 1khz, to change frequency change R and associated caps. i have some bulbs Nick, if you want some to play with, drop us a line.
From the little I know designing and building a very low distortion analogue sig source is far from simple, even at just one frequency. i have the Elektor Spot frequency schematics and other very low THD designs and white papers if you want them Nick, but they're not simple.
Andy.
