The Smart Techie was renamed Siliconindia India Edition starting Feb 2012 to continue the nearly two decade track record of excellence of our US edition.

June - 2008 - issue > Technology

Virtual Instrumentation for the Real World

Swaminathan Kumaragurubaran
Friday, May 30, 2008
Swaminathan Kumaragurubaran
Imagine the exhilaration of speeding on the German Autobahn where there are no speed limits at most stretches. You feel the acceleration all along until the speed limiter announces its presence loudly indicating that you have reached the electronically set speed limit of 250 km/hr. Exhilaration turns to apprehension as you start seeing a trail of red lights from the rapidly decelerating traffic in front, you feel the seat belts tighten as the brakes are applied, the ABS kicks in and the car stops where it has to – a few meters before the car in front.

The functionality, performance, and reliability of every product need to be tested to know how the product or device would perform in real world use. Test and Measurement Engineering focuses on this part of a product’s lifecycle. Thanks to the advancements in Test and Measurement Engineering, the cars we drive today are safer, our cell phones are reliable, and quality of products is enhanced across industry.

Test and Measurement Fundamentals
Typically, testing a product involves measuring the states and responses of various physical parameters. It is also required to control states, conditions, and responses of stimuli used to simulate real world conditions. Thousands of measurements are made in each stage of testing and a sequence of tests is carried out to simulate various real world conditions. Then the test data is analyzed to ensure compliance to various standards of design, quality, performance, reliability, and statutory requirements.

Each stage of testing would involve interfacing the product via electrical, mechanical, and software interfaces to measure the states and responses of various physical parameters and ensuring that they are within the required specifications. Most of the physical parameters such as speed, force, torque, temperature, stress, voltage, current, amplitude, frequency, power and phase noise are typically measured by using appropriate sensors that convert physical response to an electrical signal. This electrical signal is digitized by a data acquisition device. The data is available for further analysis in various forms depending on the technology used.

Typically, a measurement instrument is characterized by parameters such as its range (lower and upper limits of measurement), resolution (how small a change it can measure), accuracy (how close to calibrated value it can measure), repeatability (how repeatable it is at various measurement ranges), and speed (how fast it can sample a measurement).

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