Dashboard TOFD / Section 2: TOFD Theory / Chapter 2: Hardware

Digitizer

Digitizer

The signal arriving from the probe is analog. It needs to be transform into a digital signal.

  1. The analog signal arrives at the digitizer
  2. Data points are taken along the analog signal to create a digital equivalent. In most digital instruments, the points are taken at a rate of 100 MHz which means one point every microsecond (10-6 second)

The rule of thumb for digital signal quality is a sampling rate 5 times faster than the frequency of the probe. Hence, a 100 MHz sampling rate is sufficient for probes up to 20 MHz.