Testing the board
Experimental setup
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 tested.
Figure 1 - Picture of the experimental setup
To ease the comprehension, this setup is schematised in figure 2.
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 the device.
User guide
Here is a list of the different steps the user has to follow to get the same results.
- 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 linecat 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.