2-10 Third Order Intercept (TOI) Chapter 2 — Spectrum Analyzer Verification
2-24 PN: 10580-00279 Rev. E MS272xC MM
Procedure
1. Connect the equipment as shown in Figure 2-5. The splitter will be used as an RF combiner (the normal
RF outputs will become inputs, and the normal input will become the RF output).
2. Set the MG3692x Synthesized Signal Generator to 2399.951 MHz CW, and set the Agilent 8648D Signal
Generator to 2400.051 MHz.
3. Set the Agilent 8648D Signal Generator RF to OFF (“RF OFF” appears on the right side of the display).
4. On the ML2438A power meter, zero the sensor and set the calibration factor to 2.4 GHz.
5. Connect the power sensor to the splitter output and adjust the power of the MG3692x so that –20 dBm
appears at the splitter output (approximately +16 dBm).
6. Turn Off the RF of the MG3692x Synthesized Signal Generator.
7. On the Agilent 8648D Signal Generator, turn the RF On, and adjust the RF amplitude so that –20 dBm
appears at the splitter output (approximately +16 dBm).
8. Set the MS272xC to Spectrum Analyzer mode and then Preset the instrument. Press the Shift key, the
Sweep (3) key, Sweep Mode submenu key and then the Performance submenu key.
9. Set the MS272xC as follows:
Center Frequency: 2400.151 MHz
Span: 100 Hz
RBW: 30 Hz
VBW: 1Hz
Reference Level: –15 dBm
Atten Lvl: 0dB
Preamp: Off
10. Press the Shift key and the Sweep (3) key. Press Detection, and press RMS (a red dot appears on the
label).
11. Disconnect the power sensor from the output of the splitter and connect the splitter output to the
MS272xC Spectrum Analyzer RF In connector through the Anritsu Model 34NN50A or 71693-R adapter
(Figure 2-6 on page 2-25).
12. Turn On the RF of the MG3692x and the 8648D.
13. Press the Shift key and then the Trace (5) key. Press
Trace A Operations, and set # of Averages to 2.
14. After two sweeps have occurred (Trace Count 2/2 appears on the left of the display), turn on a marker, and
press Peak Search. Record the amplitude of the signal at 2400.151 MHz in Table A-63, “Spectrum
Analyzer Third Order Intercept” on page A-34.
15. Change the Center Frequency of the MS272xC to 2399.851 MHz. Record the amplitude of this signal in
Table A-63.
16. Determine which signal is larger (the 2399.851 MHz signal or the 2400.151 MHz signal). Use the larger
value for max in the following formula to calculate the TOI for 2400 MHz (refer to the example
calculation below the formula):
TOI = –20 + [(–20 – max) / 2] dBm
Example: Assume max = –90 dBm
Then: TOI = –20 + [(–20 – (–90))/2] = +15 dBm
17. Record the calculated 2400 MHz TOI measurement in Table A-63.
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