In virtual instrumentation, functions traditionally implemented by dedicated circuits are moved into software. Acquisition, conversion and analogue conditioning remain essential, while display, processing, automation and many measurements can change without replacing the physical instrument.
Basic structure
An A/D converter acquires the signal and transfers samples to memory; software processes them and presents the result. Generation follows the reverse path: software builds samples and a D/A converter turns them into an analogue signal.
Hardware
Probes, protection, amplifiers, converters and the computer interface.
Software
Algorithms, user interface, automation, storage and measurement calculations.
Why VA
Visual Analyser mainly uses the audio interface, bidirectional hardware already equipped with A/D and D/A conversion. PC processing power lets several instruments run together and exchange data in real time.
Advantages and limits
- Software updates and new functions
- Automation and coordinated instruments
- Low cost
- Data storage and processing
- Hardware-limited bandwidth
- Need for calibration and protection
Read more in the Visual Analyser Handbook
This page is an operational introduction. Chapter 1 — Virtual instrumentation of the forthcoming book covers theory, controls, algorithms, examples and measurement notes in much greater depth.