That distortion is from the oscilloscope. 8-bits is about 51dB and you were measuring about 50dB. Averaging or high resolution mode will not help because they do not improve linearity.
I usually find that the best “bang for the buck” in terms of audio frequency range distortion measurements are provided by audio input/capture devices. The ADCs the good audio digitizers use are quite phenomenal - and those are not all that expensive anymore either. Sure it won’t beat a modern Audio Precision analyzer, but usually you can measure THD+N over audio range to well below 100dB relative to full scale input.
There is quite a bit of equipment out there that was produced in limited numbers, discontinued, and there are no online mentions. As far as this model goes, this video is saying something about it after all :) - and you did find it!
That distortion is from the oscilloscope. 8-bits is about 51dB and you were measuring about 50dB. Averaging or high resolution mode will not help because they do not improve linearity.
this scope was in 10 bit mode :-) it is correct noise floor goto 50 something if I select 8 bit mode
@@jim9930 exactly.. the correct way is to NOTCH the fundamental, it is not that hard to do, THEN it is much easier to measure this :-)
I usually find that the best “bang for the buck” in terms of audio frequency range distortion measurements are provided by audio input/capture devices. The ADCs the good audio digitizers use are quite phenomenal - and those are not all that expensive anymore either. Sure it won’t beat a modern Audio Precision analyzer, but usually you can measure THD+N over audio range to well below 100dB relative to full scale input.
Where did you aquire this unit? I cant find anything about this model online or any for sale
There is quite a bit of equipment out there that was produced in limited numbers, discontinued, and there are no online mentions. As far as this model goes, this video is saying something about it after all :) - and you did find it!