Trigger Setting

The trigger mode determines the sweep actuation of the channel at a trigger signal detection. A channel can operate in one of the following three trigger modes:

• Continuous – a sweep actuation occurs every time a trigger signal is detected;
• Single – one sweep actuation occurs with trigger signal detection after the mode has been enabled; after the sweep is complete the channel modes changes to hold;
• Hold – sweep actuation is off in the channel, trigger signals do not affect the channel.

The trigger signal applies to the whole Analyzer and controls the trigging of all the channels in the following manner. If more than one channel window are open, the trigger activates successive measurements of all the channels which are not in hold mode. Before measurement of all channels is complete, all additional triggers are ignored. When measurement of all the channels is complete, if there is as least one channel in continuous trigger mode, the Analyzer will enter waiting for a trigger state.

The trigger source can be selected by the user from the following four available options:

• Internal – the next trigger signal is generated by the Analyzer on completion of each sweep;
• External – the external trigger input is used as a trigger signal source;
• Manual – the trigger signal is generated by pressing the corresponding softkey.
• Bus – the trigger signal is generated by a command communicated from an external computer from a program controlling the Analyzer via COM/DCOM.

The Trigger Scope specifies the scope of the triggering, whether it is for all channels (default) or for the active channel. When this function is enabled with a value of "ACTive", only active channel is triggered. When this function is enabled with a value of "ALL", all channels of the analyzer are triggered.

For example, if Trigger Scope is set to "ACTive" when Trigger > Continuous is selected for all channels, a measurement channel is automatically changed by switching over the active channel.

• To set the trigger mode, use the softkeys in the Trigger menu.
• Hold All Channels and Continuous All Channels softkeys turn all the channels to the respective mode.
• Restart softkey aborts the sweep and returns the trigger system to the waiting for a trigger state.
• To set the trigger source and scope, use the corresponding softkeys.

External Trigger (except Planar 304/1)

Point Feature

By default the external trigger initiates a sweep measurement upon every trigger event (See Figure 27 a, b). For the external trigger source, the point trigger feature instead initiates a point measurement upon each trigger event (See Figure 27 c, d).

To enable the point trigger feature for external trigger source, use the corresponding softkeys.

External Trigger Polarity

To select the external trigger polarity, use the corresopnding softkeys.

External Trigger Position

The external trigger position selects the position when Analyzer expects the external trigger signal:

• Before sampling, when the frequency of the stimulus port have been set. The frequency change of the stimulus port begins after sampling (See Figure 27 a, c).
• Before the frequency setup and subsequent measurement. The frequency change of the stimulus port begins when the external trigger arrives (See Figure 27 b, d).

Depending on the Point Feature settings the external trigger is expected before each point or before the first point of the full sweep cycle.

To select external trigger position, use the softkeys.

External Trigger Delay

The external trigger delay sets the response delay with respect to the external trigger signal (see Figure 27). The delay value has range from 0 to 100 sec with resolution 0.1 µsec.

To set the external trigger delay, use the softkeys.

1. Before Sampling, Point trigger OFF

2. Before Setup, Point trigger OFF

3. Before Sampling, Point trigger ON

4. Before Setup, Point trigger ON

Trigger Output (Cobalt models)

The trigger output outputs various waveforms depending on the setting of the Output Trigger Function:

• Before frequency setup pulse;
• Before sampling pulse;
• After sampling pulse;
• Ready for external trigger;
• End of sweep pulse;
• Measurement sweep.

Switching ON/OFF Trigger Output

To enable/disable the trigger output, use the softkeys.

Trigger Output Polarity

To select the polarity of the trigger output, use the softkeys.

Trigger Output Function

To select the function of the trigger output (See Figure 28, Figure 29), use the softkeys.