Temperature compensation
These probes employ temperature compensation to optimize measurement accuracy. Whenever a probe setting is
changed, such as Input Mode, Offset Voltage, or vertical scale factor, a temperature compensation update occurs.
Continuous temperature compensation is not done to avoid introducing noise into the probe amplifiers.
To maximize measurement accuracy when the probe is first powered on from a cold start condition, you must allow the
probe and oscilloscope a 20 minute warm-up period. After the warm-up period, you should adjust or toggle a probe setting,
such as the vertical scale factor, to trigger the temperature compensation update. Otherwise, a cold temperature
compensation value may be used, which would result in a small gain error. A fan is used to stabilize temperature and may
come on from time to time.
DSP correction
This series of probes contain S-parameter characterization data for the probe, which is downloaded to the attached
oscilloscope when the probe is first connected. The probe tips also contain S-parameter characterization data for the tip,
which is also downloaded to the attached oscilloscope when the probe tip is attached to the probe. This probe and tip
characterization data is used to generate DSP correction filters that improves high frequency measurement accuracy.
Solder tip measurement configuration
In many of the high-frequency signaling standards that the P7700 TDP7700 Series probes are designed for, a 50 Ω
termination at the transmitter is in parallel with another 50 Ω termination at the end of the transmission line path, effectively
making a 25 Ω signal source impedance. In this application, the solder tip adapter measurement configuration is designed
to pick off the transmitted signal at a location in the signal transmission path.
The input impedance for a solder tip, Z probe, varies with frequency. For a P77STFLXA tip the DC input resistance is about
50 kΩ and decreases with frequency above about 10 MHz to about 100 Ω above 10 GHz.
Figure 7: Solder tip measurement configuration
Connecting to a circuit board
TriMode tips are necessary to
complete the connection between
the P7700 TDP7700 Series probes
and your circuit. The tips are
available as both standard and
optional accessories and provide
several connection options.
Basic operation
P7700 Series TriMode™ Probes 27
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