TDC-GP21 datasheet(46/91 Pages) AMSCO

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TDC-GP21

acam messelectronic gmbh - Friedrich-List-Str.4 - 76297 Stutensee - Germany - www.acam.de

4-1

Converter Frontend

4.1

TDC - Measurement mode 1

4.1.1

General Description



Measurement range from 3.5 ns to 2.4 µs (0 to 2.4 µs between stop channels)



2 stop channels referring to one start channel each of typ. 90 ps resolution



1 stop channel referring to one start channel with typ. 45 ps resolution



20 ns pulse pair resolution



4-fold multihit capability for each stop channel



Selectable rising/falling edge sensitivity for each channel



Enable pins for windowing functionality



The possibility to arbitrarily measure all events against each other



Typical application: Laser ToF, RF ToF, ATE

Digital TDCs use internal propagation delays of signals through gates to measure time

intervals with very high precision. Figure 5 clarifies the princip al structure of such an

absolute-time TDC. Intelligent circuit structures, redundant circuitry and special methods

of layout on the chip make it possible to reconstruct the exact number of gates passed by

the signal. The maximum possible resolution strongly depends on the maximum possible

gate propagation delay on the chip.

Figure 4.1

The measuring unit is triggered by a START signal and stopped by a STOP signal. Based on

the position of the ring oscillator and the coarse counter the time interval between START

and STOP is calculated with a 20 bit measurement range.

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