Input Signal Dynamic Range; Offset Voltage - Tektronix TriMode TDP7700 Series Technical Reference

Theory of operation
CAUTION. To avoid ESD damage to the probe, always use an antistatic wrist
strap (provided with your probe), and work at a static-approved workstation
when handling the probe.
Input signal dynamic
The input signal dynamic range is bound by the maximum voltage difference
between either the A and B input of the probe tip and the probe tip ground
range
reference that the probe can accept without distorting the signal. Outside of the
input signal dynamic range, gain compression will result in increased linearity
error and clipping. The DC specifications of the probe are valid only over the
input signal dynamic range. The dynamic range is not a hard limit for signal
distortion; probe tip input voltages can slightly exceed the dynamic range limit if
a slightly higher linearity error is determined to be acceptable.
The differential and common-mode dynamic ranges for TekFlex probe tips are
derived from the single-ended dynamic range. The maximum differential signal
can be twice the single ended range since the A side can be at the positive
dynamic range limit and the B side can be at the negative dynamic range limit (or
vice versa). The maximum common-mode signal is the same as the single-ended
dynamic range limits. With the probe tip A and B offset voltages both set to 0 V,
the dynamic range will be symmetrical around that 0 V level. In this case, the
dynamic range can be considered to equal ±(dynamic range ÷ 2). If the
oscilloscope vertical scale factor is set high enough to display the full dynamic
range, the oscilloscope will momentarily add dynamic range limit annunciation
lines. These dynamic range annunciation lines can be refreshed by adjusting one
of the vertical channel knobs, such as position or scale factor.

Offset voltage

The offset voltage control sums an adjustable DC voltage with the probe signal
input. It is commonly used to nullify an input DC bias voltage to center the input
signal swing within the linear dynamic range of the probe input. The A and B
probe inputs both have an independent offset voltage control when used in A
mode or B mode respectively. The following figure shows a simplified diagram
of a TekFlex probe tip input network.
TDP7700 Series TriMode Probes Technical Reference 13