TDC-GP21 datasheet(38/91 Pages) AMSCO

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TDC-GP21

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

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Only in measurement mode 1 negative results are possible.

In measurement mode 2 only positive results are possible, given as unsigned numbers.

A non-calibrated measure is possible only in measurement mode 1.

In measurement mode 1 with calibrated data (ALU) the time intervals that have to be

measured can not exceed twice the period of the calibration clock. When measuring

bigger time intervals an ALU - overflow will occur and ’hFFFFFFFF is written in the

appropriate result register.

a. Measurement mode 1 with calibrated data (CALIBRATE = 1)

The results are given in multiples of the internal reference clock (= external reference

clock divided by 1, 2 or 4 (DIV_CLKHS)). Calibrated data are 32 bit fixed point numbers

with 16 integer bits and 16 fractional bits. Any calibrated result covers therefore 1 result

(2-16). The numbers are available in complements of 2.

Time = RES_X * Tref * 2 DIV_CLKHS = RES_X * Tref * N , with N = 1, 2 or 4

Time < 2 * Tref * 2 DIV_CLKHS

b. Measurement mode 1 without calibration (CALIBRATE = 0)

Non-calibrated data are of the type ‘Signed Integer’ and are stored as a 16 bit value in the

high word of the result registers. The bits of the low word are set to zero. The result is

represented as number of LSB and is available in complements of 2.

Time = RES_X * LSB ~ RES_X * 90 ps

c. Measurement mode 2

In measurement mode 2 the TDC-GP21 only supports calibrated measurement. The

results are given in multiples of the internal reference clock (= external reference clock

divided by 1, 2 or 4 (DIV_CLKHS)). Calibrated data are 32 bit fixed point numbers with 16

integer bits and 16 fractional bits. Any calibrated result covers therefore 1 result register.

The serial output begins with the highest bit (215) and ends with the lowest one (2-16). The

numbers are available in complements of 2.

Time = RES_X * Tref * 2 DIV_CLKHS = RES_X * Tref * N , with N = 1, 2 or 4

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