Sampling and D-A Conversion

Now, there's a lot going on here.

Suggested experiments ...

  1. Set the signal frequency to 3Hz.
  2. Set the Bits/sample to 12 bits (ie very accurate A-D conversion)
  3. Set the sampling frequency to 50Hz (ie far greater than the signal frequency)
    The sampled signal is pretty good, isn't it?
  4. Lower the sample frequency until it reaches 10Hz.
    Signal looks pretty horrid, but is is going up and down the correct number of times!
  5. Lower the sample frequency gradually until it reaches 6Hz. This is JUST twice the signal frequency. What has happened?
  6. Take the sample frequency back up to 50Hz.
  7. Now let's muck about with the bits/sample. Reduce it from 12 to 4 - that means that we only have 2^4 = 16 values of voltage available. Some distortion?
  8. Now really go for it - 2 bits/sample = 4 values of voltage. Pretty nasty, unless all you need to get from this is a frequency. This would sound really horrid!
Sampling and D-A Conversion
Sampling and D-A Conversion