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[JGO]

Can anyone refer me to measured figures of Common Mode Rejection vs frequency ?

A web search seems to indicate that Alexander Graham Bell patented it in 1881 for telephones so it is a "Good Thing " 

I seem to remember that in EEG a rejection of volts of 50Hz is achieved to monitor mvolts of signal, say 70 dB rejection. This is at 50 Hz and by my reckoning for a flat twin this will fall off  by 6dB/octave. So at 1MHz the rejection would be about 78 dB less ! ?
Twisted is said to be better but  I was once shown an article where the CMR was drastically changed by half a twist less  at 30 MHz.   Coax is less bother !


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edited by admin to fix smiley

[burakkucat]

Can anyone refer me to measured figures of Common Mode Rejection vs frequency ?

Unfortunately I am unable to do so. Such a discussion would be getting into the realm of things to which I would refer to your knowledge, opinion and judgement. 

I suspect that the Wizards of Grimbledon Down¹ would have tables that show exactly the information of which you are interested . . . but I do not know of any means of access. 


¹ A.k.a. Adastral Park, Martlesham Heath, Suffolk.