As many people might know Time-to-Digital-Converters are becoming cheaper and cheaper, while resolution increases. This is thanks to continuous improvements in CMOS technology.
Inspired by the paper "The ? counter, a frequency counter based on the Linear Regression" I thought a comparision of TDCs might be interesting.
https://arxiv.org/pdf/1506.05009v1I have currently two TDCs on the table in my lab, GP22 and TDC7200. Links below:
http://www.pmt-fl.com/tdc/tdc-time-to-digital-converters.phphttp://www.ti.com/product/TDC7200Both devices are available for <10€ so it's interesting how they perform compared to each other, right?
So here is a first simple comparision with the given example on page 10 in the manuel of TDC7200EVM:
Setting the Dual Channel Function Generator (for example: Tektronix’s AFG3102):
(a) Set channel 1 of the dual function generator to as follows (see Figure 5):
(i) Pulse 1-Cycle
(ii) Burst mode
(iii) Freq = 40kHz
(iv) Delay = 0s
(v) Amplitude = 3.3Vpp
(vi) Offset = 1.65V
(vii) Duty = 20%
(b) Set channel 2 of the dual function generator to as follows (see Figure 5):
(i) Pulse 1-Cycle
(ii) Burst mode
(iii) Freq = 40 kHz
(iv) Delay = 19us --> this is the time-of-flight (TOF)
(v) Amplitude = 3.3 Vpp
(vi) Offset = 1.65 V
(vii) Duty = 20%
Both devices are in Mode 2 and as far as I currently know with the best settings, which means quad resolution on GP22 and with the given settings described in TDC7200EVM manuel.
First resultGP22: 4933 samples in 30.2s; mean= 19000.7790687205ns; std=0.0451478954351179ns; max-min=0.336999999999534ns
TDC7200: 998 samples in 30.33s; mean=19000.0621584899ns; std=0.233032667622456ns; max-min=0.917114999996556ns
Pretty interesting results. I guess I need other TDC models to compare with.