Hello,
I have what to some of you might be a really simple question, maybe not.
I built a custom ADC and DAC for the Teensy 4 / Teensy 4.1. I'm considering selling them, but market research shows that people want these measurements. (frequency response, dynamic range, total harmonic distortion, and Signal to noise)
What's the easiest way to perform measurements of my system? Are their any tutorials you are aware of that can help me find these measurements?
Jay
I have what to some of you might be a really simple question, maybe not.
I built a custom ADC and DAC for the Teensy 4 / Teensy 4.1. I'm considering selling them, but market research shows that people want these measurements. (frequency response, dynamic range, total harmonic distortion, and Signal to noise)
What's the easiest way to perform measurements of my system? Are their any tutorials you are aware of that can help me find these measurements?
Jay
There is some interesting reading material that can be downloaded from the Audio Precision website.
If you have never even played with RMAA in the past, you may find audio measurements to have a bit of a learning curve. From sample rate / resampling issues and badly set levels to clocks too far out of sync, there are a number of things that can go wrong, and not all of them are plainly obvious to the uninitiated.
As a rule of thumb, to accurately quantify THD or dynamic range performance of a converter you need a counterpart that's at least 10 dB better in distortion / noise. You also have to avoid ground loops in your measurement setup, making sure to use galvanic isolation or correctly employing balanced connections where available.
For a more accurate noise floor measurement, you can use an external preamp of some sort, you just have to calibrate its gain. Likewise, external notch filtering or other distortion magnification is commonly employed where very low-level distortion has to be measured. These sorts of tricks generally involve doing things manually.
The go-to forum section for this kind of stuff is Equipment & Tools.
As a rule of thumb, to accurately quantify THD or dynamic range performance of a converter you need a counterpart that's at least 10 dB better in distortion / noise. You also have to avoid ground loops in your measurement setup, making sure to use galvanic isolation or correctly employing balanced connections where available.
For a more accurate noise floor measurement, you can use an external preamp of some sort, you just have to calibrate its gain. Likewise, external notch filtering or other distortion magnification is commonly employed where very low-level distortion has to be measured. These sorts of tricks generally involve doing things manually.
The go-to forum section for this kind of stuff is Equipment & Tools.
Testing to the level of current ADC/DAC requires very expensive test equipment. Rule of thumb is it must be 10 times better than what you are testing. You can do a simple loop-back, but that won't isolate the in from the out and fine tuning each for optimum performance is in the blind.
Might look at the ARS WEB and read how he does the testing.
Heck, much better than just my little Focusrite IO box is pushing Johnson noise limits.
Might look at the ARS WEB and read how he does the testing.
Heck, much better than just my little Focusrite IO box is pushing Johnson noise limits.