2: Coupler Multicurve
13
In the FP35 IM Distortion test, the analyzer presents two tones simultaneously.
The frequency distance between these two tones is set by the user. Any ampli-
tudes found at frequencies other than the original two tones is considered dis-
tortion. Just as when a harmonic distortion measurement is run, the analyzer
sweeps the tones across the entire frequency range—the only difference is that
two tones are used at a time instead of only one, as in a pure-tone sweep. See
the FP35 Operator’s Manual for more details.
To run the IM test:
1. Set up the analyzer for coupler testing as usual.
2. Enter the Coupler Multicurve screen by pressing [F3] from the Opening
screen.
3. Press [MENU] to enter the local menu.
4. Use the [
5
,
6
] keys to select DISTORTION.
5. Use [
3
,
4
] to select the type of IM distortion sweep you want to make. Use
TOTAL to get the most IM distortion data.
6. Press [NEXT] to go to the Advanced Coupler Multicurve screen.
7. Use the [
5
,
6
] keys to select IM FREQ DIFF.
8. Use [
3
,
4
] to select the difference between the two tones used in the mea-
surement.
9. Press [EXIT] to close the local menu.
10. Press and hold down the [F4] key for half a second. This will bring up a
pop-up menu containing all the available source types.
11. Use the [
5
,
6
] keys to select DIST.
12. Press [START/STOP] to complete the selection and close the pop-up menu.
13. Press [START/STOP] again to perform the IM distortion sweep. The test will
stop automatically when it is finished. See Figure 2.2.5.
