The Spectrum Application
R&S
®
FPC
75
User Manual 1178.4130.02 ─ 07
The third order intermodulation (TOI) measurement analyzes the intermodulation prod-
ucts that occur at the output of the DUT and calculates the third order intercept point.
The IP3 is the theoretical intercept point of the DUTs desired output level and the level
of the intermodulation products. It is thus a measure of the DUTs linearity.
To perform the TOI measurement, you need two signals with the same level on slightly
different frequencies, combine them and feed them into the RF input of the R&S
FPC.
Signal 1
Signal 2
Combiner
Analyzer
DUT
Selecting the TOI measurement
1. Press the "Meas" key to open the measurement menu.
2. Select the "Measurement Mode" menu item to select the measurement.
3. Select the "Third Order Intermod." menu item.
The R&S
FPC starts to measure the third order intermodulation.
To do this, the R&S
FPC places two markers (marker 1 and marker 2) on the signal
peaks (assumed to be the fundamentals) and two markers (marker 3 and marker 4)
on the third order intermodulation products. The R&S
FPC calculates the third
order intercept point from the level difference between the first 2 markers and the
markers 3 and 4 and displays the result in the diagram header.
Searching for signals
A signal search is an easy way to update the marker position and thus the measure-
ment results (for example if the signal frequencies have changed).
1. Press the "Meas" key to open the measurement menu.
2. Select the "Search Signals" menu item.
The R&S
FPC does a signal search, positions the marker accordingly and updates
the TOI results.
14.2.3
Power Measurements on TDMA Signals
Access
: "Meas" > "Measurement Mode" > "TDMA Power"
Remote commands required to configure power measurements on TDMA signals:
●
Chapter 19.12.1.5, "TDMA Power"
Available with the optional "Advanced Measurements" application.
TDMA (time division multiple access) is a channel access method in which several
users share a channel. The channel is divided into several time slots (a period of time).
Each user is assigned to a certain time slot. GSM is a transmission standard that uses
TDMA, for example.
Measurements and Result Displays
