Chapter 3 — Options Verification 3-2 Option 31, GPS Frequency Accuracy Verification
MS272xC MM PN: 10580-00279 Rev. E 3-3
2. Press the Shift key and then the System (8) key.
3. Press the GPS submenu key, then press the GPS On/Off submenu key to turn on the GPS.
4. When the GPS fix is acquired, the GPS indicator at the top of the LCD display turns green. The latitude
and the longitude are displayed next to the GPS indicator.
5. After about three minutes, the Reference Source indicator in the lower left corner of the LCD display
changes to GPS High Accy.
6. If the GPS fix is acquired using the Anritsu 2000-1528-R GPS antenna outside, then bringing the
instrument inside causes a loss of satellite tracking. A red cross appears on the green GPS indicator, and
the Reference Source indicator changes to Int Hi Accy.
Test Procedure
1. Connect the external 10 MHz Reference to the Anritsu MG3692x Synthesized Signal Generator.
2. Connect the output of the Synthesized Signal Generator to the Spectrum Analyzer RF In of the
MS272xC, as shown in Figure 3-1.
3. On the MS272xC, change the mode to Spectrum Analyzer and preset the instrument.
4. Set the MG3692x output to 7 GHz CW, with an RF output level of –30 dBm.
5. On the MS272xC, press the Amplitude main menu key, and set the Ref Lvl to –10 dBm.
6. Press the Freq main menu key and set the Center Freq to 7.0 GHz.
7. Press the Span main menu key and set the Span to 10 kHz.
8. Press the BW main menu key and set RBW to 100 Hz.
9. Press the VBW submenu key and set VBW to 30 Hz.
10. Press the Marker main menu key, press the More submenu key, then set Counter Marker to On and press
the Back key.
11. Press the Peak Search submenu key.
12. Note the Reference Source display and use the appropriate row to record the data in the following steps.
13. Record the marker frequency into the “Measured Value” column of Table A-64, “Option 31, GPS Receiver
Frequency Accuracy” on page A-35.
14. Subtract the marker value from 7 GHz, record the result into the Error column of Table A-64, and verify
that it is within specification.
15. If the value of Reference Source indicates GPS High Accuracy, then remove the GPS antenna and wait
until the Reference Source indicates Int Hi Accy and repeat Step 10 through Step 14 if necessary.
Note The following test can be used to verify frequency accuracy to either specification.
Note Do not connect the external 10 MHz Reference to the MS272xC Spectrum Master.