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TDC-GP1 Measurement Range 2

ACAM TDC-GP1 Time to Digital Converter Circuit

It is possible to extend the maximum time interval by using a pre-divider. The resolution in LSB remains unchanged by that. In this mode the high-speed unit of the TDC does not measure the whole time interval but only time intervals from START and STOP to the next rising edge of the reference clock (finecounts). In between the finecounts the TDC counts the number of periods of the reference clock (coarsecount). The measurement range is extended to 216 x Tref and may reach 200 ms.

General Circuit Features

In measurement range 2 only 1 channel is available with 4 possible STOPs in normal resolution and 3 possible STOPs in high resolution.

The active time of the high-speed unit as the main current drain is reduced remarkably.

As opposed to measuring range 1, in measuring range 2 the result is the sum of different fine and coarse-count results. Therefore it is necessary in measuring range 2 to make a calibration. During a calibration the TDC measures 1 and 2 periods of the reference clock.

Timing

(click to enlarge)