
5.3. Electromagnetic Interference 61
Signal processing electronic components, such as opamps, multipli-
ers, digital processors, and the like, have a limited ability to reject
common-mode noise on differential inputs. If noisy signals are
expected, it is good practice to attenuate the noise before it arrives at
the sensitive circuitry. Once inside, it is too late, and noise overloads
can cause anomalies that are difficult to analyze. Figure 5.3 shows a
multiplier chip as an example. The circuit is presumably immune to
high-frequency noise because of the common-mode rejection of the
multiplier. But if the noise level is not really known, it is a good ...