Configuration of the FDR settings is accomplished by selecting the Settings
softkey. The settings softkey allows you to access the FDR settings screen
or select the default settings.
The FDR Settings screen provides the following four settings for setting
up the LST1700 to measure the cable system.
- resolution of the measurement
- velocity of propagation
- cable compensation (on/off)
- cable attenuation
Resolution of Measurement
The resolution of measurement determines the number of data points, maximum
distance of, and distance resolution/accuracy of the measurement. This
box contains LOW (64pts), MEDIUM (128pts), HIGH
(256pts), and ULTRA (512pts).
This setting greatly affects the time per measurement cycle, with LOW
being quick (least accurate) and ULTRA being slow (most accurate). NOTE: The default setting for the Resolution
of Measurement is LOW.
VOP
The velocity of propagation (VOP) is a property of the cable in use and
greatly affects the measurement accuracy. NOTE:
VOP values available are 0.3 through
1.0. The default the VOP value is .820.
NOTE: Changing either the VOP or the cable attenuation manually
will automatically set the cable type field to Manual Settings.
Cable Compensation
The Cable compensation box contains ON and OFF.
Cable Attenuation
The cable attenuation @ 50MHz entry is only used if this field is set to
ON. The cable attenuation direct entry field is used to calibrate the
distance measurement for distant breaks. NOTE:
Cable attenuation values available are 0.01
through 3.5. The default cable attenuation value is 2.1.