Three analog input (AI) signals available to the PCI-9812 may be sampled simultaneously. Three digital signals then combine with the 12-bit analog signal to form a 16-bit signal, which in turn is fed into the computer. On the surface level, there seem to be a synchronous relationship between the three digital signals and the AI signals.

In fact, the A/D converter implemented in the PCI-9812, which is a Burr-Brown ADS801 has a 7-level flip-latch that results in the three digital channels being 8 sampling cycles different from those on the AI channels.

Emitted signals are split using a divider circuit (e.g. 74HC163). In such a way, the resulted QA~QC signals are converted into 000, 001, 010, 011...which may be used as the frame differentiation signals. The ADS801 has a 7-level flip-latch that results in the three digital channels being 8 sampling cycles different from those on the AI channels.

Emitted signals are split using a divider circuit (e.g. 74HC163). The resulted QA~QC signals are converted into 000, 001, 010, 011...which may be used as the frame differentiation signals.