251
Tel: 886.909 602 109 Email: [email protected]
www.salukitec.com
216
generator is acceptable. A sweep frequency signal is input in the I channel of the vector signal
generator. The I/Q modulation generates a double-sideband modulation signal, and the signal
analyzer is used to observe the frequency response of the double-sideband signal. When testing, the
vector signal generator is set to ALC open loop. The sweep time of the sweep signal generator is set
to 50 s.
b) Test block diagram
Fig.7.10 External FM Frequency Response Test
c) Test equipment
Spectrum analyzer
1 set
S1465D
1 set
d) Test procedures
Step 1. Power on and reset it, and warm it up for at least 30 minutes.
Step 2. Connect the device as shown in Fig.7.10.
Step 3. Set the vector signal generator:
CW 900 MHz, Power Level 0 dBm
Amplitude ALC Loop State ALC-ON Search
I/Q
I/Q Data Source
EXT 50Ω I/Q Modulate ON.
Step 4. Set the sweep signal generator:
Freq Start 1 MHz
Freq Stop 200 MHz Sweep Time 50 s
Power Level 0 dBm
Step 5. Set up the signal analyzer as follows:
Center Freq 900 MHz
Span 300 MHz Amplitude 1 dB/Div Trace Max. Hold
Observe the power difference between the maximum and minimum power points of the trace on
the signal analyzer and divide the power difference by 2 to be the frequency response.
Step 6. Test the external modulation bandwidth frequency responses of the tested vector
signal generator at 1.8 GHz, 2.4 GHz, 6 GHz, 18 GHz, and 35 GHz respectively according to
the above steps.
7.1.1.4 Source voltage standing wave ratio test
a) Test description
This test is used to determine whether the source voltage standing wave ratio index of the signal
generator meets the requirements by using the power meter, directional coupler, and sliding load. The
source voltage standing wave ratio reflects the degree of influence of the reflected signal on the
output power of the final signal generator when the signal generator mismatches during output. Refer
to 5.15.14 in GB 12114-2013 for test methods.