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               shown that the presence of a depth leads to a significant error in the measurement of

               velocity, which  is caused by the passage  of an acoustic wave through the  layer of

               contact fluid, which is formed when the surface of the control object and the contact

               area of the converter are not parallel. The influence of the depth on the time delay of

               the  acoustic  signal  using  different  types  of  contact  fluids  has  been  investigated.  A

               method for estimating the magnitude of  the error in determining the SAW velocity

               caused by the presence of depressions is proposed, which is based on measurements

               using contact fluids with different acoustic wave velocities.

                     A technique has been developed for a converter with rigidly coupled excitation

               and  receiving  prisms  for  determining  the  speed  distribution  of  the  SAW,  which

               combines the ability to change the measurement step with no need to determine its

               magnitude  with  high  accuracy.  It  is  shown  that  the  contribution  of  the  error  of

               determining the displacement of the converter to the error of determining the velocity

               depends on the magnitude of the change of velocity in the adjacent areas and is equal

               to the product of the error of determination of the displacement of the converter by

               the  magnitude  of  the  relative  change  of  these  velocities.  The  use  of  the  proposed

               approach allows to determine the rate of SAW in one area of the sample relative to

               another. The technique created allows us to optimize the step of measuring the SAW

               rate for non-uniform objects of control.

                      The  criterion  for  selecting  the  optimal  value  of  the  measurement  step  to

               determine  the  distribution  of  the  SAW  rate  in  non-uniform  objects  of  control  is

               formulated.  According  to  the  proposed  criterion,  the  selection  of  the  measurement

               step is made on the basis of the properties of the control object and the characteristics

               of the measuring equipment. We also propose an algorithm by which you can select a

               measurement step that meets the stated criterion.

                     A technique for measuring the velocity of acoustic waves was developed based

               on  the  use  of  a  continuous  reference  signal  with  the  frequency  of  excitation  of  an

               acoustic  wave  and  a  comparison  of  the  passage  time  of  an  acoustic  wave  in  the


               studied object of control and a comparison sample. The technique allows the use of
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