18 Oscilloscope Utility Settings
388 InfiniiVision 7000B Series Oscilloscopes User’s Guide
Setting Rear Panel Options
The rear panel options you can set are:
• The function of the 10 MHz REF connector.
• The source of the TRIG OUT signal.
To set the reference signal mode
The 10 MHz REF BNC connector on the rear panel is provided so you can:
• Supply a more accurate sample clock signal to the oscilloscope, or
• Synchronize the timebase of two or more instruments.
Sample clock and frequency counter accuracy
The oscilloscope’s timebase uses a built- in reference that has an accuracy
of 15 ppm. This is sufficient for most uses. However, if you are looking at
a window that is very narrow compared to the selected delay (for
example, looking at a 15 ns pulse with the delay set to 1 ms), significant
error can be introduced.
Using the built- in sample clock, the oscilloscope’s hardware frequency
counter is a 5- digit counter.
Supplying an external timebase reference
When you supply an external timebase reference, the hardware frequency
counter is automatically changed to an 8-digit counter. In this case, the
frequency counter ([Meas] > Select > Counter) is as accurate as the external
clock.
For more information on the hardware frequency counter, see
“Counter” on page 162.