Ceyear 4051 Series, Руководство пользователя

Страница: 176 / 751

4. Operating Instruction
4.2 Advanced operation guide
162
Fig. 4.81 Results of Spurious Emission Measurement
4.2.18 Spectral emission mask
4.2.18.1 Basic concept
Spectral emission mask (SEM) measurement includes spurious emission inside and outside the band and is
targeted at spurious signals inside the frequency range close to carrier signals. Analysis bandwidth for
spurious measurement may differ for varied frequency range of carrier shift. To facilitate observation and
judgment, spurious threshold level is given for each frequency range starting right from the carrier signal
according to relevant standards, which is connected to form the spectral mask. Only spurious signals located
within such spectral mask can be measured. Therefore, the spectral mask can be used as a direct indicator of
whether spurious component of one signal exceeds the standard.
Measurement setup key is for detailed setting of relevant parameters of multicarrier measurement, while
measurement control key is for single or continuous measurement switch.
4.2.18.2 Measurement Example
This section mainly introduces how to carry out spectrum emission mask measurement of W-CDMA (3GPP)
signal (use a signal generator to simulate a W-CDMA signal). SEM will assign power within carrier
bandwidth and power within offset channel to compare with power level specified in the Standard.
Step 1. Set signal source as below:
 Set up W-CDMA signals.
 Set frequency on signal source to 1.960GHz.
 Set signal amplitude to -10dBm.
Step 2. Connect the radio frequency output port of the signal source to that of the analyzer. As shown in
Fig. 4.82: