LeCroy DA18000AC, Instruction Manual

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Reference Information
DA18000AC-OM-E Rev A
6-3
mode component increases, the effects of stray parasitic capacitance and inductance in
determining the AC component becomes more pronounced. The CMRR becomes smaller
as the frequency increases. Hence the CMRR is usually specified in a graph of CMRR ver-
sus common mode frequency.
The common mode frequency in these graphs is assumed to be sinusoidal. In real life appli-
cations, the common mode signal is seldom a pure sine wave. Signals with pulse wave
shapes contain frequency components much higher than the repetition rate may suggests.
As such, it is very difficult to predict actual performance in the application for CMRR versus
frequency graphs. The practical application of these graphs is to compare the relative com-
mon mode rejection performance between different probes and amplifiers.
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