Instrument Functions
R&S
®
FSVA/FSV
404Operating Manual 1176.7510.02 ─ 09
t4: End of useful part, to be used for statistics (after 578 µs)
t5: End of burst (after 602 µs)
The instrument has to be configured as follows:
Trigger Offset t2 – t1 = 25 µs now the gate ranges are relative to t2
Range1 Start t3 – t2 = 15 µs start of range 1 relative to t2
Range1 End t4 – t2 = 553 µs end of range 1 relative to t2
3.3.5.9 Measuring the Third Order Intercept Point (TOI)
In order to measure the third order intercept point (TOI), a two-tone signal with equal
carrier levels is expected at the R&S FSVA/FSV input. Marker 1 and marker 2 (both
normal markers) are set to the maximum of the two signals. Marker 3 and marker 4 are
placed on the intermodulation products.
The R&S FSVA/FSV calculates the third order intercept point from the level difference
between the first 2 markers and the markers 3 and 4 and displays it in the marker field.
The third order intercept point is measured using the "TOI" softkey, see "TOI"
on page 313.
A measurement example is described in "Measurement Example – Measuring the
R&S FSVA/FSV's Intrinsic Intermodulation" on page 142.
About TOI Measurement
If several signals are applied to a transmission two-port device with nonlinear charac-
teristic, intermodulation products appear at its output at the sums and differences of
the signals. The nonlinear characteristic produces harmonics of the useful signals
which intermodulate at the characteristic. The intermodulation products of lower order
have a special effect since their level is largest and they are near the useful signals.
The intermodulation product of third order causes the highest interference. It is the
intermodulation product generated from one of the useful signals and the 2nd harmonic
of the second useful signal in case of two-tone modulation.
The frequencies of the intermodulation products are above and below the useful sig-
nals. The Figure 3-19 shows intermodulation products P
I1
and P
I2
generated by the two
useful signals P
U1
and P
U2
.
Measurement Functions
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