High Performance ADCs

Hi-Techniques uses only market leading Successive Approximation Register (SAR) type ADCs in our Synergy products. The SAR is the only ADC type found in high-quality, high-resolution digital oscilloscopes as it allows for selectable filtering. A smooth roll-off, or Gaussian Filter, is necessary in the time domain to prevent a large preshoot and overshoot and steep roll-off, or FIR-type Filter, is needed to provide the widest bandwidth for frequency domain measurements. The Synergy provides both filter types on all of our boards to make our systems a true general purpose data acquisition system.

Why ADC Technology Matters

These days many data acquisition companies attempt to market their 24-bit systems as providing superior accuracy. This would be true if we didn't account for the vast difference in ADC technology. The fact is that virtually all competitive 24-bit systems on the market use the Sigma Delta type ADC.

Sigma Deltas were developed for the consumer audio marketplace as a cheap high-resolution alternative and therefore are embedded with steep (FIR) filters. These steep filters unfortunately cause a very large preshoot and overshoot when used in the time domain on any signal with a fast rise or fall time. Waveform quality is compromised by up to a 20% amplitude error for many applications when using a Sigma Delta ADC for these measurments. This error is called the "Gibbs Phenomenon".
View ADC Tech Note
This short Tech Note details the major differences in ADC technology