R&S FSQ Signal Analyzer - Rohde & Schwarz

R&S FSQ Getting Started
➢ Press the TOI softkey.
Measuring the Spectrums of Complex Signals
The R&S FSQ activates four markers for measuring the intermodulation
distance. Two markers are positioned on the useful signals and two on the
intermodulation products. The 3rd order intercept is calculated from the level
difference between the useful signals and the intermodulation products. It is
then displayed on the screen:
Fig. 2.3 Result of intrinsic intermodulation measurement on the R&S FSQ. The 3rd order
intercept (TOI) is displayed at the top right corner of the grid
The level of a Signal Analyzer’s intrinsic intermodulation products depends on
the RF level of the useful signals at the input mixer. When the RF attenuation
is added, the mixer level is reduced and the intermodulation distance is
increased. With an additional RF attenuation of 10 dB, the levels of the
intermodulation products are reduced by 20 dB. The noise level is, however,
increased by 10 dB.
6. Increasing RF attenuation to 10 dB to reduce intermodulation products.
➢ Press the AMPT key.
➢ Press the RF ATTEN MANUAL softkey and enter 10 dB.
The R&S FSQ’s intrinsic intermodulation products disappear below the noise
floor.
2.6 Operating Manual 1313.9681.12 - 01