Giga-tronics 2508B, Руководство по эксплуатации

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Performance Verification Giga-tronics 2500B Series Microwave Signal Generators
Page 114 Operation Manual, Part Number 34737, Rev C, June 30, 2011
Table 71: Amplitude Modulation Accuracy
Amplitude Modulation Accuracy
Step Action
1. Connect the equipment as shown in Figure 52 on page 113.
Connect the function generator output to the EXT AM IN connector on the rear of the 2500B.
Connect the spectrum analyzer timebase output to EXT REF IN on the rear of the 2500B.
2. Allow the equipment to warm up for at least 30 minutes.
3. Set the 2500B for the following settings:
External AM State: On
Sensitivity: 30 %/V
Level: 0 dBm
CW frequency: 10 MHz
4. Set the spectrum analyzer to the following settings:
Reference Level: +5 dBm
Span: 5 kHz
Sweep time: AUTO
Resolution Bandwidth: 30 Hz
Video Bandwidth: 30 Hz
5. Set the function generator for a 1 kHz sine wave output at 2.00 V peak-to-peak.
NOTE: Measure the output of the function generator using a precision Digital Voltage Meter to
ensure that its output is 2.00 Vp-p. This must be as exact as possible.
6. Set the spectrum analyzer to the test frequency (output frequency of the 2500B). Center the signal
using Peak Search and Marker to Center Frequency functions.
7. Activate the Delta Marker function and press the Next Peak function or move the marker to the next
peak.
8. Measure and record the AM Depth in the appropriate column in the datasheet:
If this is the first time through the test, record the AM Depth in the “30 %/V” column.
If this is the second time through the test, record the AM Depth in the “50 %/V” column.
If this is the third time through the test, record the AM Depth in the “75 %/V” column.
9. Measure the difference in dB of one sideband and the carrier. Use the following formula to
determine the AM depth in percentage:
AM 30 % = -16.5 dB
AM 50 % = -12 dB
AM 75 % = -8.5 dB
The measurement should be with a 10 % range of the AM sensitivity setting.
10. Deactivate the AM function of the 2500B, and repeat steps 6 through 9 for the remaining 2500B
output test frequencies in Datasheet 6, recording the AM depth for each in the appropriate column.