HP 86037B, Instruction Manual

Page: 28 / 204

2-10
Operation
The Main Window
Measurement Speed Parameters area
The Measurement Speed Parameters area allows you to adjust measurement
times based upon the number of acquired measurement data points at each
wavelength step. These are the measurement points used by the system’s net-
work analyzer. Of the three standard settings, the normal measurement speed
setting provides the greatest accuracy and the longest measurement time.
(You can enter up to 1601 data points using the custom selection.)
Under certain situations, the normal setting (201 measurement points) may
not offer substantially greater accuracy than the fastest setting (3 measure-
ment points).
Figure 2-3 shows how measured group-delay uncertainty varies
with measurement speed, the sensitivity setting, and the loss through upthe
test device. (To learn how the sensitivity setting affects measurement speed
refer to “Sensitivity” on page 2-16 .) Notice that for devices with less than 10
dB loss, very high accuracy can still be achieved using only 3 measurement
points and normal sensitivity. In this situation, using more points and higher
sensitivity would not gain any more accuracy but would take more time.
Figure 2-3. Typical group delay uncertainty variation versus loss of test device