Calibrations; Measurements - HP 53131A Operating Manual

In This Guide

Calibrations

If your Counter contains other than the current firmware revision,
the following calibration features are different:
• The calibration functions are in the Utility menu instead of the
Calibration menu, which is accessed by pressing and holding the
front-panel Utility key and then cycling POWER key.
• Calibrations are not protected by a security code.
• A calibration count does not exist to aid in monitoring the number of
calibrations performed.
• A more accurate Time Interval calibration (FINE TI) is not available.
See the section titled "Using the Calibration Menu" in Chapter 2 of the
HP 53131A/132A Operating Guide for details.

Measurements

If your Counter contains other than the current firmware revision,
the following measurement capabilities are different:
• Ratio channel selections Ratio 2 to 1 and Ratio 3 to 1 (for those
counters equipped with Channel 3) are not available.
• Ratio "AUTO-armed" does not automatically extends gate to capture
sufficient edges.
If Channel 1 input frequency is less than approximately 10 Hz,
the Ratio gate time is not extended to capture sufficient Channel 1
edges to produce a valid measurement. Default gate time is 100 msec,
which is not long enough to capture two edges on a low-frequency
signal. The user is required to extend the gate by switching to TIME
arming, and selecting a gate time appropriately long.
• Sensitivity for firmware revision below does not have adjusted
controls to LO and MED sensitivity.
In some Counters that contained firmware revision 3317,
LO sensitivity fails to correctly count very high frequency signals.
Operating Guide xxi