Operating Manual Vol 1 - ES Documentation

Digital ModulationSMIQ2.10.5.3 Asynchronous Interface for External Modulation DataThe SERDATA interface on the rear of SMIQ serves for the asynchronous serial transmission ofmodulation data. The characteristics of this RS-232-C interface is described in Annex A.For a defined start with specific modulation data it has to be made sure that the backup memories in theRS-232 transmitter and receiver are deleted. The following setting sequence in the menu is required:1. Carry out desired settings for digital modulation in menu.2. Select data source SERDATA using SOURCE - SOURCE SERDATA.3. Make connection to external data source, but do not yet start external data source.4. Switch off digital modulation using STATE OFF.5. Set TRIGGER MODE ARMED_AUTO.In this state, SMIQ is ready for reception, but discards data that are read in via SERDATA.6. Switch on digital modulation with STATE ON.7. Start external data source.The read-in data are written into the receiving buffer. Only if this buffer is filled can SMIQ react to atrigger event.8. Activate trigger event to start digital modulation.Note:The baud rate has to be selected at least 25% higher than the bit rate of the digitalmodulation. If SMIQ has not enough data, the error message "Data underrun" will beissued in the status line.2.10.5.4 External Control SignalsThe external control signals for envelope control BURST GATE and LEV ATT can be applied via theSERDATA interface at the rear of SMIQ. The signal for CW control can also be applied to this interface.Note:The use of control signals from lists in combination with external modulation data is notpossible.1125.5555.03 2.98E-9