Operating information, Operating principles, Repetitive triggers – BNC 745 User Manual

Page 13: Single shot triggers

Model 745 Digital Delay Generator.

November 2013

6- O

PERATING

NFORMATION

Operating Principles

The principle of the programmable delay generator is described in the figure 4 below:

Figure - 4.

Principle

Trigger source can be provided by the TRIG IN input, by an internal trigger, by a software command

trigger. Repetitive, single shot trigger and burst modes are available with internal and external

sources. An asynchronous single shot and burst mode are also available.

Repetitive triggers

When the external trigger source is selected a rising edge on “TRIG IN” starts a delay sequence. The

sequence is depicted on Figure - 6. It has to be noticed that a Prescaler value can be used to divide

the Trig Ext input signal frequency.

To get this feature, the user has to select ‘EXT’ as trigger source on the device via the front panel or

via remote control (web page, Ethernet link).

If the internal trigger source is selected, the user can specify the needed trigger source via the front

panel or via remote control (web page, Ethernet link). 2 frequency generators derived from input

clock can be used as repetitive triggers: IN1 and IN2 corresponding to programmable Frequency 1

and 2. The use of internal trigger is depicted on Figure - 8. Frequency generation restarts when a

push on the ESC button is detected while Frequency/Period menu is displayed.

Note: The internal period P1 et P2 can only be increment by step of 5ns.

Single Shot triggers

3 single shot modes are available: one synchronous to the external source (SSE), one to an internal

source (SS1 synchronous to Frequency 1, SS2 synchronous to Frequency 2) and the last, an

asynchronous one (LSS).

Each single shot mode is triggered by a software command. Software trigger command is available

either via remote control or via front panel (by pressing ESC button when items #6 to 13 are

displayed or by using item #20).

Single shots synchronous to external source is depicted on Figure - 6. The same principle can be

applied to any of the internal sources.

Model 745 User Manual