Con Guring The Test Set - HP 84125A User Manual

Con guring the Test Set
CAUTION
Note
6-2 Making Measurements
If measured results using peak detection are signi cantly below
the limit line (approximately 6 dB), further measurements are not
required.
The HP 84125A/B microwave EMI measurement test system has
two high-gain ampli ers to achieve the needed sensitivity. There is
a possibility of overloading the second ampli er if the signal into
the rst ampli er is too large. The signal level out of the second
ampli er should be less than +10 dBm or 117 dB  V, as displayed on
the EMC analyzer. Special care should be taken to avoid overloading
the system with signals greater than +10 dBm or 117 dB  V; this may
result in making invalid measurements.
1. Determine the fundamental frequency of the equipment under test
(EUT). For this example, a fundamental frequency of 830 MHz will
be used for the cellular telephone.
2. Make a list of the harmonic frequencies that you will need to test.
For 830 MHz, the ten harmonic frequencies to be tested are:
1.66 GHz
2.49 GHz
3.32 GHz
4.15 GHz
4.98 GHz
5.81 GHz
6.64 GHz
7.47 GHz
8.30 GHz
3. The fundamental signal is usually 40 dB above the harmonics.
In order to avoid overloading the EMC analyzer rst converter,
a high-pass lter must be added. To lter out the fundamental
frequency of 830 MHz, install the 1.5 GHz lter in the test set.
Refer to Figure 4-2 to assist you with this procedure.
For an HP 84125B system, make sure that the 1 to 18 GHz antenna
(HP 11966E) is installed in the test set. Refer to Chapter 4 to assist
you with this procedure.
4. On the EMC analyzer, press the following key sequences:
a. ,
4 5 4
PRESET MODE
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Verify that EMC ANALYZER is underlined. If not, press
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
EMC ANALYZER . This ensures full range of analyzer
functionality.
b.
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
HP84125A/B PRESET ,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
1.5GHZ to 18GHZ .
.
5
NNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
CONT , SELECT CONFIG ,