This section is dedicated to the experimental setup to test the TDC.
This setup is represented on figure 1. The two first input channels are
Figure 1 - Picture of the experimental setup
To ease the comprehension, this setup is schematised in figure
Figure 2 - Schematics of the experimental setup
Pulses are sent from a function generator (Agilent 33220A). These pulses
have a square form, 5 ns of rising/falling edge. Their minimum value is
0 V and their maximum value is 5 V. Their frequency is set to 1.5 Hz
with a duty cycle of 50 %.
These pulses are sent in a Minicircuit HF splitter (ZFSC-2-2500). The
splitter outputs are connected to the TDC by cables. One analogue delay
line is inserted in the path of one channel. This line allows us to
change the global length of one channel by small increments. The
equivalent length on both channels is more ore less the same.
The pulses are first cleaned by the use of CMOS gates and then sent in a
filter described in the filter-section before entering
the ADC board. The operational amplifiers on the board need to be
powered with +5 and -5 V (We used HP E3612). The +5 V can also be used
for the CMOS gates.
The different parts of the TDC (the CMOS gates, the filter board and the
ADC board) are connected with SMA nuts to reduce the cable length inside
Here is a list of the different steps the user has to follow to get the
Install the experimental setup
Connect with an external PC to the Microzed via SSH (it is possible
to connect it via serial interface as well). To boot on the Linux,
the MicroZed jumpers have to be placed correctly (JP1 in position 1,
JP2 in position 1 and JP3 in position 2)
On Linux, configure the FPGA by loading the bitstream
root/python/zboard_top_demo.bit, this can be done by entering the
command line cat root/python/zboard_top_demo.bit > /dev/xdevcfg.
Run the script root/python/tdc_demo.py with python 3. If multiple
versions of python are installed on the device, this can be done by
entering the command /usr/bin/python3 python/tdc_demo.py.
The script is done to do 50 measurements and give the mean value and
the standard deviation.