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FUNCTION REFERENCE

DELAY

Description:

Delay is the term that is used to define the time difference between the trigger point of an acquisition and the starting point of the resulting trace. In an analog oscilloscope, the trigger point is at the beginning of a trace, and the delay is said to be zero. The use of a Delayed Timebase introduces a delay between the trigger point of the Main Timebase and the start of the trace which is displayed with the Delayed Timebase.

Three types of Delay.

This family of oscilloscopes has three types of adjustable delay :

1.Delay controlled by the DELAY control on the front panel. This is the amount of time delay between the start of the Main Timebase and the Delayed Timebase. This delay applies to the Analog mode, as well as to the Digital mode.

2.A delay between the trigger point and a signal acquisition. This delay is used to ‘position’ the acquired input signal with respect to the trigger point. This type of delay can be ‘positive’, as well as ‘negative’. The result is the acquisition of posttrigger or pretrigger waveform data, respectively.

This delay is available in the digital mode only and is controlled with the TRIGGER POSITION control.

3.Delay caused by counting EVENTS. Available in the digital mode only. The use of EVENTS delay causes the acquisition to start after a user selectable number of events has been counted.

Delay

A full description is given under Delayed Timebase.

Trigger position

Pretrigger is used to observe a portion of the signal that occurs before the trigger point. This trigger point is then indicated in the screen by a marker (s). The maximum pretrigger is the acquisition length. In this case, the trigger point marker is positioned on the right side of the screen and the entire record contains pretrigger information. The pretrigger view is indicated (in divisions) in the bottom of the screen.

Posttrigger is used for time delay and is expressed in seconds or fractions thereof. The maximum delay depends on the setting of the main timebase. Maximum trigger delay is 100 divisions; the resolution is 1/50 of the timebase TIME/DIV setting.

Event delay

Event delay postpones triggering until a specific number of trigger events have occurred. The trigger event is defined in the EVENT DELAY sub menu of the TB MODE. Its definition consists of a signal source and a trigger level (event level).

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Fluke PM3370B user manual Full description is given under Delayed Timebase, Trigger position, Event delay