Soundcard as Test Instrument

It’s safe to say that every modern PC for home or office use has an internal soundcard. In general, the quality of the PC’s sound subsystem is sufficient to allow measurements in the audio frequency range. With software in abundance on the Internet, nothing to keep you from turning your PC into an oscilloscope or a function generator.These days it’s hard to find a new PC without an internal soundcard or a sound chip integrated on the motherboard. Whatever the configuration, the ‘sound’ hardware in the PC often offers advanced features like 5.1-surround sound. Although such ‘bells and whistles’ will not be used by everyone, technical developments in PC sound technology have resulted in much improved audio reproduction characteristics as compared with a few years ago. Not only do we have a wide frequency range available, there’s also a good signal/noise ratio and low distortion. All in all, the perfect behaviour to enable you to perform the occasional measurements in the audio range, especially if you do not want to splash out on a real oscilloscope or an external PC ‘scope. Today, advanced soundcards are available at reasonable prices from, among others, Creative, Hercules and Terratec. These products offer 24-bit resolution and 192-kHz sampling. An excellent starting point for a modest PC-based measurement system!