UNI-T UTS3000B/A Series User Manual page 37

Figure
Note
Directional coupler must have high degree of isolation between the two inputs so that the two source
signals will not cross modulate.
2. Set the frequency of a signal source (signal generator) to 299.95MHz, the frequency of the other
signal source to 300.05MHz, so the frequency spacing is 100kHz. The amplitudes of the two sources
are set to the same value (in this case, -5dbm).
3. Set the center frequency and sweep span of the spectrum analyzer:
Press [Default]>Reset
Press [FREQ]>Center Frequency>300>MHz，Span>500kHz
4. Reduce the resolution bandwidth until the distortion product can be seen:
Press [BW]>Rotate the Rotary Knob
5. Move signal to reference level:
Press [Peak]>Marker→>→Ref Level
6. Decrease the resolution bandwidth until the distortion can be seen:
Press [BW]>Rotate the Rotary Knob
7. Activate the second marker and use next peak to move it to the peak of distortion signal:
Press [Marker]>Marker Mode>Delta△
Press [Peak]>Next PK
8. Measure another distortion signal:
Press [Marker]>Marker Mode>Normal
Press [Peak]>Next PK
9. Measure the difference between the measured signal and the second distortion signal:
Press [Marker]>Marker Mode>Delta△
Press [Peak]>Next PK
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Instrument Setting of Third-Order Intercept Signal
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