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TDC-GP1 Resolution Adjust Mode

Another important feature of the GP1 is the Resolution Adjust Mode. In this mode the resolution of the TDC is quartz-accurately adjustable to a programmable value and simultaneously for both channels. As a reference for the regulation loop a clock is used which is derived from the external reference clock. The adjustment of the resolution happens via software by setting registers. The resulting resolution is defined by the programmer!

The resolution remains stable due to the changes in the measurement core voltage, which is regulated via PLL (Phase Locked Loop). The external circuit of the PLL regulation needs only a few small and cheap components.

In this mode the resolution does not depend on the production lot, the temperature or the supply voltage. It is absolutely long-term stable. In this mode a separate calibration is not necessary.

Timing

(click to enlarge)

Regulation Circuit