Electric measuring device for measuring the propagation delay of an electrical signal

Claim 1

A method for measuring a propagation delay of an electrical, electromagnetic or acoustic signal between a transmitter and a receiver located at any distance from the transmitter, wherein a transmitted signal delivered by the transmitter is a square-wave pulse, and a received signal reaching the receiver, as a result of distortion of the square-wave pulse during propagation, is a group of waves having positive half-waves which increase in amplitude over several cycles and then decay, and whose period of vibration T is an integral multiple of a fundamental frequency of the transmitted square-wave pulse, said method comprising the steps of: a) transmitting the square-wave pulse (S 1 ) having an instant of transmission (T 0 ) of a leading edge; b) scanning the received signal (S 2 ) with a threshold voltage (V) which is controlled in a plurality of steps; c) comparing an instantaneous value of the threshold voltage (V) with an amplitude of each positive half-wave of the received signal (S 2 ); d) storing the instantaneous value of the threshold voltage if the particular positive half-wave exceeds the threshold voltage value; e) determining a plurality of propagation delays (T A , T B , T C , T D ), wherein each of said plurality of propagation delays (T A , T B , T C , T D ) corresponds to one of said plurality of positive half-waves, by defining the propagation delay for each positive half-wave to be a zero-crossing point following a point at which the amplitude of the positive half-wave falls below the instantaneous threshold voltage (V); f) decreasing the threshold voltage (V) by a value ΔV; g) repeating steps a) through f) n times to determine a plurality of groups (A, B, C, D) of threshold voltage values, wherein each of said plurality of groups of threshold voltage values corresponds to one of the plurality of positive half-waves of the received signal (S 2 ); and h) determining a plurality of peak amplitude values (V A , V B , V C , V D ), wherein each of said plurality of peak amplitude values corresponds to a maximum value of each of said plurality of groups of threshold voltage values; i) forming an envelope of the group of waves of the received signal (S 2 ) from said plurality of peak amplitude values (V A , V B , V C , V D ) and said plurality of propagation delays (T A , T B , T C , T D ); j) determining a point of intersection of the envelope with a baseline 0 of the group of waves of the received signal (S 2 ), said point of intersection being defined as the instant (T 1 ) of a first appearance of the received signal (S 2 ) in the receiver; and k) determining the propagation delay (T S ) of the received signal from a difference between the instant of transmission (T O ) of a leading-edge of the square-wave pulse (S 1 ) and the instant (T 1 ) of the first appearance of the received signal (S 2 ).

Claim 2

A method for measuring a propagation delay of an electrical, electromagnetic or acoustic signal between a transmitter and a receiver located at any distance from the transmitter, wherein a transmitted signal delivered by the transmitter is a square-wave pulse, and a received signal reaching the receiver, as a result of distortion of the square-wave pulse during propagation, is a group of waves having positive half-waves which increase in amplitude over several cycles and then decay, and whose period of vibration T is an integral multiple of a fundamental frequency of the transmitted square-wave pulse, said method comprising the steps of: a) transmitting the square-wave pulse (S 1 ) having an instant of transmission (T 0 ) of a leading edge; b) scanning the received signal (S 2 ) with a threshold voltage (V) which is controlled in a plurality of steps; c) comparing an instantaneous value of the threshold voltage (V) with an amplitude of each positive half-wave of the received signal (S 2 ); d) storing the instantaneous value of the threshold voltage if the particular positive half-wave exceeds the threshold voltage value; e) determining a plurality of propagation delays (T A , T B , T C , T D ), wherein each of said plurality of propagation delays (T A , T B , T C , T D ) corresponds to one of said plurality of positive half-waves, by defining the propagation delay for each positive half-wave to be a zero-crossing point following a point at which the amplitude of the positive half-wave falls below the instantaneous threshold voltage (V); f) decreasing the threshold voltage (V) by a value ΔV; g) repeating steps a) through f) n times to determine a plurality of groups (A, B, C, D) of threshold voltage values, wherein each of said plurality of groups of threshold voltage values corresponds to one of the plurality of positive half-waves of the received signal (S 2 ); and h) determining a plurality of peak amplitude values (V A , V B , V C , V D ), wherein each of said plurality of peak amplitude values corresponds to a maximum value of each of said plurality of groups of threshold voltage values; i) forming an envelope of the group of waves of the received signal (S 2 ) from said plurality of peak amplitude values (V A , V B , V C , V D ) and said plurality of propagation delays (T A , T B , T C , T D ); j) determining a point of intersection of the envelope with a baseline 0 of the group of waves of the received signal (S 2 ), said point of intersection being defined as the instant (T 1 ) of a first appearance of the received signal (S 2 ) in the receiver; and k) determining the propagation delay (T S ) of the received signal from a difference between the instant of transmission (T O ) of a leading-edge of the square-wave pulse (S 1 ) and the instant (T 1 ) of the first appearance of the received signal (S 2 ).