Tektronix P7313SMA, Technical Reference

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Operating Basics
Common-Mode Signal Range.
The common-mode signal range is the maximum voltage that you can apply to each
input, with respect to earth ground, without saturating the input circuitry of the probe. A common-mode voltage that
exceeds the common-mode signal range may produce an erroneous output waveform even when the differential-mode
speci
fi cation is met.
Differential-Mode Signal Range.
The differential-mode signal range is the maximum voltage difference between the
plus and minus inputs that the probe can accept without distorting the signal. The distortion from a voltage that is too large
can result in a clipped or otherwise distorted and inaccurate measurement. The differential mode signal range is dependent
on the probe attenuator setting as shown. (See Figure 4.)
For a more detailed description of the differential mode dynamic range, see Differential Measurement Topology .
Figure 4: Differential and Common-Mode operating ranges
Common-Mode Rejection.
The common-mode rejection ratio (CMRR) is the ability of a probe to reject signals that are
common to both inputs. More precisely, CMRR is the ratio of the differential-mode gain to the common-mode gain. The
higher the ratio, the greater the ability to reject common-mode signals.
Probe Ampli fi er Outputs.
The P7313SMA probe has a differential signal output. The positive polarity output is
connected to the oscilloscope through the TekConnect probe interface. The inverted polarity output is connected to the Aux
Output SMA connector on the top of the probe.
The positive polarity main output is automatically scaled by the intelligent TekConnect probe interface to compensate for
probe attenuation and display the differential signal voltage at the probe inputs. The inverted Aux Output is an attenuated
version of the differential signal input, which must be manually accounted for in signal measurements or processing.
P7313SMA Technical Reference 7