Method and apparatus for measuring acoustic wave velocity using impulse response

A method of determining the temperature of a fluid in a noisy environment, said method comprising the steps of:

• (a) transmitting successive bursts of random acoustic waves through the fluid from a transmitting location to a receiving location, said waves having a spectrum of interest and a plurality of frequencies;
• (b) coupling electrical signals corresponding to said acoustic waves transmitted from said transmitting location to a computing device;
• (c) coupling electrical signals corresponding to the acoustic waves arriving at the receiving location to the computing device;
• and
• (d) determining the transmit time of the acoustic waves between the transmitting location and the receiving location by
• (1) obtaining the impulse response from the electrical signals corresponding to said transmitted waves and from the electrical signals corresponding to the received waves, whereby said impulse response is defined by the relationship:
• h(.tau.)=F.sup.-1 [S.sub.xy /S.sub.xx ]
• whereby
• x(t)=the electrical signals corresponding to said transmitted waves
• y(t)=the electrical signals corresponding to said received waves
• X(f).DELTA.F[x(t)]
• Y(f).DELTA.F[y(t)]
• S.sub.xy .DELTA.X*Y
• S.sub.xx .DELTA.X*X
• and (2) determining the point of maximum value of the impulse response, to transit time of the acoustic waves being represented by the value .tau. at which the point of maximum value of the impulse response is found and
• (e) computing the temperature of the fluid from the transmit time determined in step (d).

A system for measuring a transit time of acoustic waves in a fluid in a noisy environment, said system comprising:

• transmitter transducer means for generating random acoustic waves for transmission through the fluid from a transmitting location to a receiving location;
• means for producing electrical signals corresponding to the acoustic waves generated by said transmitter transducer means;
• receiver transducer means for sensing the acoustic waves arriving at the receiving location and for producing electrical signals corresponding to the received acoustic waves;
• and
• computing means for receiving the electrical signals from said producing means and said receiver means and for determining the transit time of the acoustic waves between the transmitting location and the receiving location by
• (1) obtaining the impulse response of the electrical signals corresponding to said transmitted waves and from the electrical signals corresponding to the received waves, whereby said impulse response is defined by the relationship:
• h(.tau.)=F.sup.-1 [S.sub.xy /S.sub.xx ]
• whereby
• x(t)=the electrical signals corresponding to said transmitted waves
• y(t)=the electrical signals corresponding to said received waves
• X(f).DELTA.F[x(t)]
• Y(f).DELTA.F[y(t)]
• S.sub.xy .DELTA.X*Y
• S.sub.xx .DELTA.X*X
• and (2) determining the point of maximum value of the impulse response, transit time of the acoustic waves being represented by the value .tau. at which the point of maximum value of the impulse response is found.

A system for determining the temperature of a fluid in a noisy environment, said system comprising:

• transmitter transducer means for generating successive bursts of random acoustic waves for transmission through the fluid from a transmitting location to a receiving location, said bursts having a spectrum of interest and plurality of frequencies;
• means for producing electrical signals corresponding to said acoustic waves generated by said transmitter transducer means;
• receiver transducer means for sensing the acoustic waves arriving at the receiving location and for producing electrical signals corresponding to the received acoustic waves;
• and
• computing means for receiving the electrical signals from said producing means and said receiver means and for determining the transit time of the acoustic waves between the transmitting location and the receiving location by
• (1) obtaining the impulse response of the electrical signals corresponding to said transmitted waves and of the electrical signals corresponding to the received waves, whereby said impulse response is defined by the relationship:
• h(.tau.)=F.sup.-1 [S.sub.xy /S.sub.xx ]
• whereby
• x(t)=the electrical signals corresponding to said transmitted waves
• y(t)=the electrical signals corresponding to said received waves
• X(f).DELTA.F[x(t)]
• Y(f).DELTA.F[y(t)]
• S.sub.xy .DELTA.X*Y
• S.sub.xx .DELTA.X*X
• and (2) determining the point of maximum value of the impulse response, the transit time of the acoustic waves being represented by the value .tau. at which the point of maximum value of the impulse response is found;
• said computing means further including means for determining the temperature of the fluid medium form the transit time.