Chapter 4. Sound Card-based Oscilloscope
The title of this chapter is Sound Card-based Oscilloscope; however, I am going to start by highly recommending an external USB sound card such as this one from Creative Labs:
Model SB-1090 from Creative Labs (Image courtesy: eBay)
This model from Creative Labs (http://us.creative.com/p/sound-blaster/sound-blaster-x-fi-surround-5-1-pro) has very impressive specifications. Whether you decide to go with an internal or external card, you will want one with similar specifications:
- Playback: Up to 24 bits/96 kHz 5.1
- Signal-to-Noise ratio (SNR): Less than 100 dB
- Total harmonic distortion + noise at 1 kHz: 0.01 percent
- Recording: Up to 24 bits/96 kHz
Note the 96 KHz sample rate. This gives us a maximum measurable frequency of 48 KHz at an SNR of less than 100 dB. You most likely won't get these specifications from an internal card. Get the highest sample rate and highest SNR your budget will allow.
