JDS Uniphase CellAdvisor JD780A Series User Manual page 98

JD780A Series Analyzers
2.
To set the maximum reference value on the Y-axis manually, complete the following steps:
a. Press the Reference Level soft key.
b. Enter a value by using the numeric keys or the rotary knob with 10 dB increments.
c. Press the dBm soft key or the ENTER hard key.
3.
To set the attenuation option, select one from the following choices:
–
To set the input attenuator's level automatically, select Attenuation > Auto.
NOTE
It is recommended that you set the Attenuation to Auto in most situations so that the
level of the input attenuator can be set automatically according to your input signal level.
–
To set the input attenuation manually up to 55 dB to optimize S/N, complete the following
steps:
a.
b.
c.
d.
–
To couple the input attenuator's level with your reference level setting, select Attenuation >
Couple.
As you increase the reference setting, the attenuation level also increases acoordingly.
Optional. To change the scale unit:
1.
Select More (1/2) > Units.
2.
Select the unit of the display scale: dBm, dBV, dBmV, dBµV, V, or W.
The scale unit on the screen changes accordingly.
Scale per division
You can use the Scale/Div feature available for the spectrum measurement screen. It represents the
value of one division on the horizontal scale. The default setting is 10 dB per division and the
maximum value can be set up to 20 dB.
Procedure
To set the scale per division:
1.
Press the AMP/SCALE hard key.
2.
Select More (1/2) > Scale/Div.
3.
Enter a value between 1 and 20 by using the numeric keys.
4.
Press the dB soft key to complete the entry.
Pre-amplifier
You can turn the internal pre-amplifier on to correct and compensate for the gain of the preamp so that
amplitude readings show the value at the input connector.
98
Select Attenuation > Manual.
Press the Attenuation Value soft key to set the level.
Enter a value between 0 and 55 in fives by using the numeric keys.
Press the dB soft key or the ENTER hard key.
Using Interference Analyzer