Measuring Waveforms
TDS 684A, TDS 744A, & TDS 784A User Manual 3–103
Run an SPC anytime you wish to ensure that the measurements you make are
made with the most accuracy possible. You should also run an SPC if the
temperature has changed more than 5 C since the last SPC was performed.
NOTE. When making measurements at volts/division settings less than or equal to
5 mV, you should run SPC at least once per week. Failure to do so may result in
the oscilloscope not meeting warranted performance levels at those volts/div
settings. (Warranted characteristics are listed in the Performance Verification
and Specifications manual.)
To run an SPC, do the following steps:
1. Power on the digitizing oscilloscope and allow a 20 minute warm-up before
doing this procedure.
2. Disconnect any input signals you may have connected from all four input
channels.
STOP. When doing steps 3 and 4, do not turn off the oscilloscope until signal
path compensation completes. If you interrupt (or lose) power to the instrument
while signal path compensation is running, a message is logged in the oscillo-
scope error log. If such a case occurs, rerun signal path compensation.
3. Press SHIFT UTILITY ➞ System (main) ➞ Cal (pop-up) ➞ Signal
Path (main) ➞ OK Compensate Signal Paths (side).
4. Wait for signal path compensation to complete (up to 15 minutes). While it
progresses, a “clock” icon (shown at left) is displayed on-screen. When
compensation completes, the status message will be updated to Pass or Fail
in the main menu.
5. Verify the word Pass appears under Signal Path in the main menu. (See
Figure 3–62.)