VXI VT1433B manual Measurement Process, Measurement Setup and Control

Models: VT1433B

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Measurement Process

VT1433B User's Guide

Using the VT1433B

Measurement Process

Measurement Setup and Control

When the VT1433B makes a measurement, the measurement itself consists of two phases: the measurement initialization and the measurement loop. Each of these phases consists of several states, through which the measurement progresses.

The transition from one state to the next is tied to a transition in the Sync/Trigger line (one of the TTL trigger lines on the VXI back plane). A state (such as Idle) begins when the Sync/Trigger line goes low. The Sync/Trigger line then remains low as long as the state is in effect. When the Sync/Trigger line goes high it signals the transition to the next state. See the sections “Measurement Initialization” and “Measurement Loop” below for more details about these transitions. During all the transitions of the Sync/Trigger line, the clock line continues with a constant pulse.

The Sync/Trigger line is “wire-OR’d” such that all modules in a multiple-module system (within one mainframe) must release it for it to go high. Only one VT1433B is required to pull the Sync/Trigger line low. In a system with only one VT1433B, the Sync/Trigger line is local to the module and not is routed to a TTL TRIGGER line on the VXI back plane.

Sync/Trigger Line

Idle

Trigger

Pre-arm

Arm

Meas

 

 

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End of

 

 

 

 

 

 

 

 

 

 

 

 

 

State

 

State

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3-7: Transitions between states

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Page 63
Image 63
VXI VT1433B manual Measurement Process, Measurement Setup and Control