Clock precision

The DAC IC function is to convert digital data in analog. To perform this function the DAC need to made two main tasks:

  • convert the digital number in an analog voltage or current with a best precision related at the number of bits available
  • place this analog value with the best precision in the time axis

The first task depend mainly from the DAC IC itself, the second from the precision of the time reference (master clock). In the next figure we can see what happens if the clock edge is not exactly always placed in the same position; there is an uncertainty on the position of the clock edge called jitter.

Jitter

It is easy to understand that the clock precision is one of the most important parameter in the analog signal reconstruction. So in our DAC units we use high precision and stable clock reference. But the precision of the clock itself is not sufficient to ensure the expected precision; the clock distribution paths from the source to the ICs that use the clock is critical and need to be carefully designed.

Giu, 12, 2016

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