Operating Manual Vol 1 - ES Documentation

Fading SimulationSMIQ2.9 Fading SimulationBy means of the option Fading Simulator SMIQB14, multipath fading signals with 6 independenttransmission paths can be generated.Important:The Fading Simulator can only be operated with the complex baseband signalsI and Q. Therefore, it is necessary to switch on either Vector Modulation or DigitalModulation.IQ modulatorcos( ωt)RF up/down converterIQextextBasebandfadingsimulatorRF OUTModulationcoder(SMIQB20)I Qsin( ωt)Fig. 2-36Fading simulator in the SMIQThe input signals for the fading simulator can either be applied to the modulation inputs I and Q or willbe generated in the SMIQ by the optional Modulation Coder (SMIQB20). The output signals of the fadingsimulator will be passed to the IQ Modulator and then be mixed to the RF.SMIQ can also be equipped with two Fading Simulators (SMIQB14 and SMIQB15). The second fadingoption provides another 6 transmission paths.If only one fading simulator is built in, output signals I and Q are available at the I FADED and Q FADEDconnectors.If two fading simulators are built in, the sum signal of the two fading options with 12 fading paths areavailable at the I FADED and Q FADED connectors.Note:If option SMIQB17 (NDSIM) is fitted, the faded, noisy and distorted I/Q signals are presentat the I FADED and Q FADED connectors. If neither noise nor distortion is desired, setDISTORTION in the NOISE/DIST menu to ON and select the predefined TEST list underSELECT LIST to make sure that an output signal is present at the I FADED and Q FADEDconnectors.A selectable internal calibration of the fading simulator allows internal compensation of DCoffset voltages. The calibration routine should be called up after temperature changes ofmore than 5 degree in menu UTILITIES-CALIB-VECTOR MOD.1125.5555.03 2.70 E-9