Keysight N9913B, Руководство пользователя

Страница: 72 / 896

72 Keysight N9938-90006 User’s Guide
DTF (Distance to Fault) Measurements
DTF Measurement Settings
The center frequency for the measurement is determined from the
calculated (Stop – Start) frequency values (seen on the second page of
DTF Settings):
The Loss value for the measurement is interpolated from the Freq/Loss pairs at
the Center Freq:
The correction for loss at 5 meters in one direction: 0.18 dB/m * 5m = 0.9 dB.
All DTF measurements correct for loss for travel down the DUT and back, so
double the correction: 0.9 dB * 2 = 1.8 dB.
Window Settings
Window settings provide the ability to choose between optimizing DTF
measurements for resolving closely-spaced faults or for the ability to measure
low-level faults.
How to select Window settings
1. Press Meas Setup 4
>
Settings
2. Then press arrows to move to the Window row.
3. Then press Edit .
4. Then press Window and choose from the following:
— Maximum (Maximum – Optimized for dynamic range) the noise
floor is lowered to provide the ability to measure low-level
responses. (Default setting)
— Medium – Compromise between Minimum and Maximum window
settings.
— Minimum – Best Response Resolution, providing the ability to
resolve between two closely-spaced responses.
5. Then press Done Edit .
6. Again press Done .
Calculated Start = 2.0 MHz
Calculated Stop = 3.598 GHz
Center Freq = 1.80 GHz
1 GHz = 0.1 dB/m
1.8 GHz = 0.18 dB/m
2 GHz = 0.2 dB/m