Anritsu AWGN MU368060A - Manual (Page 30)

Section 5 Sample Calibration
5-4
(4) Set the output level for this unit so that the indication value of the
power meter becomes the total power found in Step (2). This com-
pletes calibration to the –73 dBm/3.84 MHz noise level at the input
connector terminal of the receiver.
<Level accuracy>
See Section 5.1.1 for level accuracy.
<Points>
When –69.55 dBm is not able to be directly measured by the power meter,
insert a fixed attenuator into the receiver input and perform calibration
up to the necessary level of attenuation.
However, the calibration value for the attenuation of the fixed attenuator
should be measured in advance. Calibration accuracy for the fixed at-
tenuator is added to the level accuracy.
5.1.3 Measuring the level of the outputted noise
Measurement of the noise signal level outputted at an unknown level is
explained here.
A sample power setting with a 7.68 MHz noise signal bandwidth and 3.84
MHz calculated bandwidth is shown below.
< Measurement procedure>
(1) The following parameters should be set for this unit.
Digital Mod : On
System : Noise1
Noise Bandwidth : 7.68 MHz
Calculate Bandwidth : 3.84 MHz
(2) Measure the total noise power using the power meter.
Read the Calculated Level on the display. With the parameter set in
Step (1), this value should be –3.45 dBm. Figure out the noise power
for the calculated bandwidth using the formula below:
Noise power for the calculated bandwidth = power meter indication +
(–3.45 dB)
<Level accuracy>
Consider the level accuracy for this measurement. It is figured out using
the following formula:
Level accuracy
= Band calculated accuracy (Calculated Level accuracy) + power
meter accuracy
= ±0.6 dB (when the noise band is 7.68 MHz) + power meter ac-
curacy