A system for measuring a propagation delay (to) of a device under test (DUT) , the system comprising: a first measurement unit , wherein the first measurement unit comprises: a first frequency generator configured to produce a first periodic signal with a first frequency; a first transmitter port ; a first receiver port ; and a first comparator ; a second measurement unit , wherein the second measurement unit comprises: a second frequency generator configured to produce a second periodic signal with a second frequency; a second transmitter port ; a second receiver port ; and a second comparator ; wherein, the first transmitter port of the first measurement unit is configured to transmit the first periodic signal from the first frequency generator to the DUT , wherein the first periodic signal is further transmitted to the second receiver port of the second measurement unit as a first delayed periodic signal ; the second transmitter port of the second measurement unit is configured to transmit the second periodic signal from the second frequency generator to the DUT , wherein the second periodic signal is further transmitted to the first receiver port of the first measurement unit as a second delayed periodic signal ; the first comparator of the first measurement unit is configured to calculate a first comparison phase output (Ø 12 ) by comparing a phase of the first periodic signal and the second delayed periodic signal ; and the second comparator of the second measurement unit is configured to calculate a second comparison phase output (Ø 21 ) by comparing a phase of the second periodic signal and the first delayed periodic signal , wherein the propagation delay (t 0 ) is calculated by combining the first comparison phase output (Ø 12 ) and the second comparison phase output (Ø 21 ). a first measurement unit , wherein the first measurement unit comprises: a first frequency generator configured to produce a first periodic signal with a first frequency; a first transmitter port ; a first receiver port ; and a first comparator ; a first frequency generator configured to produce a first periodic signal with a first frequency; a first transmitter port ; a first receiver port ; and a first comparator ; a second measurement unit , wherein the second measurement unit comprises: a second frequency generator configured to produce a second periodic signal with a second frequency; a second transmitter port ; a second receiver port ; and a second comparator ; wherein, a second frequency generator configured to produce a second periodic signal with a second frequency; a second transmitter port ; a second receiver port ; and a second comparator ; wherein, the first transmitter port of the first measurement unit is configured to transmit the first periodic signal from the first frequency generator to the DUT , wherein the first periodic signal is further transmitted to the second receiver port of the second measurement unit as a first delayed periodic signal ; the second transmitter port of the second measurement unit is configured to transmit the second periodic signal from the second frequency generator to the DUT , wherein the second periodic signal is further transmitted to the first receiver port of the first measurement unit as a second delayed periodic signal ; the first comparator of the first measurement unit is configured to calculate a first comparison phase output (Ø 12 ) by comparing a phase of the first periodic signal and the second delayed periodic signal ; and the second comparator of the second measurement unit is configured to calculate a second comparison phase output (Ø 21 ) by comparing a phase of the second periodic signal and the first delayed periodic signal , wherein the propagation delay (t 0 ) is calculated by combining the first comparison phase output (Ø 12 ) and the second comparison phase output (Ø 21 ). <EOS>