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Calculating IMD

Question asked by serhiy on Apr 20, 2012
Latest reply on Apr 24, 2012 by jpearson

Hi All!

For the Analog devices OP amps the IMD is measured by ITU-R method, according MT-053 tutorial (http://www.analog.com/static/imported-files/tutorials/MT-053.pdf), but often in the other OP amps IMD is measured according SMPTE method, when use 60Hz and 7kHz signals combined in a 12 dB ratio. How can I recalculate IMD SMPTE to IMD ITU-R?

 

And for the AD8007/8008 according the datasheet IMD is 77dBc

( fC = 19.5 MHz to 20.5 MHz, RL = 1 kΩ, VO = 2 V p-p

Third-Order Intercept is 42.5),

but if I calculate in compliance with the MT-053 tutorial:

Why is the difference so big?

Thank You.

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