Selects the trigger mode for DME modulation signals. In "Reply Mode", you can only work with an external trigger signal.
"Auto" | The DME modulation signals are generated continuously. |
"Ext Triggered" | The DME modulation signals are triggered by an external trigger event. The trigger signal is supplied via the PULSE EXT connector. |
"Ext Gated" | The DME modulation signals are gated by an external gate signal. The signal is supplied via the PULSE EXT connector. |
"Ext Power Sensor" | Sensor R&S NRP-Z81 provides the trigger signal. An external DME interrogation signal is feed into a sensor. The 50 % voltage point of this signal is used by the power sensor to generate the trigger for the R&S SMA. The R&S SMA simulates the ground station ("Reply Mode") and sends the reply signal after the set trigger delay. |
("Ext Triggered" and "Ext Power Sensor" only)
Sets the delay between the external trigger and the first DME output pulse (50 % voltage point of first pulse). In "DME Reply" mode, this parameter simulates the defined delay of the DME transponder and twice the run time of the signal (from interrogator to transponder and back). The delay is a measure of the range distance. Thus, the two values are interdependent according to:
Delay = X/Y mode delay + range distance * 12.359 nm/µs,
where:
X mode delay = 50 µs, Y mode delay = 56 µs
Changing one value automatically changes the other value.
Remote command:("Ext" trigger only)
Sets the polarity of the active slope of an applied trigger at the PULSE EXT connector.
"Positive" | The DME modulation signals are triggered on the positive slope of the external trigger signal. |
"Negative" | The DME modulation signals are triggered on the negative slope of the external trigger signal. |
("Ext Gate" only)
Sets the polarity of the active slope of an applied trigger at the PULSE EXT connector.
"Normal" | The DME modulation signal is generated while the gate signal is high. |
"Inverse" | The DME modulation signal is generated while the gate signal is low. |
("Ext Trigger" or "Ext Gate" only)
Selects the input impedance for the external trigger and gate signal input (10 kOhm or 50 Ohms).
Remote command:("Ext Power Sensor" only)
Performs a normalization of the test setup. The function measures the delay due to the R&S NRP-Z81 sensor is and subsequently considers the value in the trigger delay.
For normalization, connect the sensor directly to the RF output of the R&S SMA. "Normalize Trigger Delay" determines the delay between RF input and trigger output of the sensor. This value is sensor specific and is stored on the R&S SMA. The value is valid as long as the same sensor is used.
Remote command:("Ext Power Sensor" only)
Determines the trigger level = 50 % voltage point of first pulse of the external DME interrogation signal.
After connecting the R&S NRP-Z81 sensor to the external interrogation signal source, "Search Trigger Level" determines the trigger point.
Execute the search function at each change of the level of the external DME signal.
Remote command:("Ext Power Sensor" only)
Indicates the trigger level, e.g. 9.92 dBm for an external signal with a peak level of 15.94 dBm.
Remote command:n.a.
("Ext Power Sensor" only)
Activates the auto zero function.
Zeroing calibrates the external power sensor by adjusting its reading at zero signal power. For this purpose, the RF power source must be switched off or disconnected from the sensor. If a Rohde & Schwarz power sensor receives an input power during the zeroing process, it aborts zeroing and generates an error message. Zeroing takes a few seconds, depending on the sensor model. Refer to the documentation of your power sensor for more information.
Tips for zeroing
- During warm up after switching on or connecting the instrument
- After a substantial change of the ambient temperature
- After fastening the power sensor module to an RF connector at high temperature
- After several hours of operation
- When low-power signals are to be measured, e.g. less than 10 dB above the lower measurement limit.
- Switch off the RF power source for zeroing, but do not disconnect it from the power sensor. This proceeding keeps the thermal equilibrium, and the zeroing process also compensates the noise that superimposes the measured signal (e.g. from a broadband amplifier).
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