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PostPosted: Wed Jul 10, 2013 11:00 am 
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Location: UK (temporarily)
I think that curve from jsr's unit looks the same as (or at least very close to) the curve from rainwarrior's once the lowpass filter is removed.


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PostPosted: Wed Jul 10, 2013 11:21 am 
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My recording was also running at a higher frequency (I hadn't made it with catching the DAC characteristics in mind, the only saw wave recording I had on hand was at 440Hz). If I ran it at a lower frequency it'd probably look a lot like jsr's. The errors do look like they're around the same place, and of similar magnitude.


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PostPosted: Wed Jul 10, 2013 11:29 am 
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Try a test that plays square waves [0 0 0 ... 0 1 1 1 ... 1], [1 1 1 ... 1 2 2 2 ... 2], through [62 62 62 ... 62 63 63 63 ... 63], with a period of 1000 Hz or so. Waveforms like that should coast through any audio-frequency band-pass filter, isolating the contribution of the DAC from the contribution of the analog band-pass that comes after it.


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PostPosted: Wed Jul 10, 2013 2:43 pm 
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Joined: Thu Oct 07, 2004 2:47 am
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I tested it on a higher frequency and yeah it looks more similar to rainwarrior's now.

Anyway it's a minor issue I guess, but it is audible on waves with low number of harmonics. NEZplug++ actually emulates this and the output is very similar to the measured ones.


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