- According to the IBM Dictionary of Computing (which cites International Organization for Standardization Information Technology Vocabulary as the source), response time is: The elapsed time between the end of an inquiry or demand on a computer system and the beginning of a response; for example, the length of the time between an indication of the end of an inquiry and the display of the first character of the response at a user terminal. There is also the concept of perceived response time, which is the time a user senses as the beginning of input and the end of the response. It is actually possible (though not usual) for perceived response time to be too fast (it can be mildly disconcerting if a system responds almost instantly). However, this is not the usual complaint.
LAST UPDATED: 11 Apr 2007 http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci212896,00.html
//---//---//---//---//---//---//---//---//---//---//---//---//---//---// Electrical Engineering Glossary Definition for Response Time Glossary Term: Response Time
Definition The time for a sensor to respond from no load to a step change in load. Usually specified as time to rise to 90% of final value, measured from onset of step input change in measured variable.
Problem: What is meant by the settling time parameter (ts)?
Solution: The settling time parameter, ts, is defined as the time required for the output voltage to settle within the specified error band of the final value with a step change at the input. It is also known as total response time, ttot. It is expressed in units of s.
It takes a finite time for a signal to propagate through the internal circuitry of an op amp. Therefore, it takes a period of time for the output to react to a step change in the input. In addition, the output normally overshoots the target value, experiences damped oscillation, and settles to a final value.
The following figure shows ts graphically. Settling time is a design issue in data acquisition circuits when signals are changing rapidly. An example is when using an op amp following a multiplexer to buffer the input to an A to D converter. Step changes can occur at the input to the op amp when the multiplexer changes channels. The output of the op amp must settle to within a certain tolerance before the A to D converter samples the signal.
tsu Setup Time JEDEC – The time interval between the application of a signal at a specified input terminal and a subsequent active transition at another specified input terminal. TI – The time interval between the application of a signal that is maintained at a specified input terminal and a consecutive active transition at another specified input terminal. NOTE: 1. The setup time is the time interval between two signal events and is determined by the system in which the digital circuit operates. A minimum value is specified that is the shortest interval for which correct operation of the digital circuit is specified. NOTE: 2. The setup time may have a negative value, in which case the minimum limit defines the longest interval (between the active transition and the application of the other signal) for which correct operation of the digital circuit is specified. Setup time is tested by switching an input to a fixed logic level at a specified time before the transition of the other input (see Figure below). The device passes if the outputs switch to their expected logic levels and fails if they do not. Setup times are not checked simultaneously with other inputs or other recommended operating conditions. For additional information about setup time, refer to the TI application report, Metastable Response in 5-V Logic Circuits, literature number SDYA006.
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