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SMPTE inter-modulation test?

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SMPTE inter-modulation test?

Postby Cupwise » Thu Mar 03, 2011 4:54 pm

what purpose is the test file with the "SMPTE inter modulation distortion test" in the latest tip of the month?
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Re: SMPTE inter-modulation test?

Postby enriquesilveti » Sun Mar 06, 2011 9:27 pm

No specific purpose, just show how SMPTE recommend to do it. (http://books.google.es/books?id=d7ft6F8 ... &q&f=false). I prefer the simple method from Simulanalog (http://www.simulanalog.org/clip.pdf)

We spend all the time talking about inter modulation distortion but we test it with simple sine tones, that is not a real situation, 2 sine tones mixed is a better example, very easy to see if you use the 1 kHz + 1.2 kHz example.

Important note: by definition if the DUT (device under test) is not lineal apply 1 kHz through the DUT and 1.2 kHz through the DUT and then sum will not the same than sum both signal before and then apply it through the DUT.
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