Anritsu S113C Uživatelská příručka stáhnout pdf (Strana 70)

Figure 4-5 shows an example of a typical DTF return loss trace.

In the above example:

Marker M1 marks the first connector, the end of the Site Master phase stable Test

Port Extension cable.

Marker M2 marks the first jumper cable.

Marker M3 marks the end of the main feeder cable.

Marker M4 is the load at the end of the entire transmission line.

Procedure - DTF-SWR Mode

The following steps explain how to measure DTF in SWR mode.

Step 1. Press the

MODE key.

Step 2. Select the

DTF-SWR using the Up/Down arrow key and press ENTER.

Step 3. Follow the same procedure as DTF-Return Loss Mode, above.

Resolution

There are three sets of data points (130, 259 and 517) available in the Site Master. The fac-

tory default is 259 data points. By increasing the number of data points the measurement

accuracy and transmission line distance to measure will increase.

Step size =

(. )( )15 10

´ Vp

Where V

is the relative propagation velocity of the cable and DF is the stop frequency mi-

nus the start frequency (Hz).

The maximum distance is: D

max

= step size ´ (# of datapoints – 1)

Increasing the data points increases the sweep time and increases the accuracy of the mea

surement.

4-9

Chapter 4 Cable & Antenna Measurements

Figure 4-5. Typical DTF Return Loss Trace

SgLabs

www.sglabs.it

tel. +39 0755149360

SgLabs

www.sglabs.it

tel. +39 0755149360

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Anritsu S113C Uživatelská příručka Strana 70