Weak Signal Detection Based-on DSP Technique Of Coriolis Massflow Meter

Coriolis Massflow Meter (CMF) is the fastest growing type of massflow measurement technique, which has most advantages in the field of the direct massflow measurement. Presently, the experimental setup is designed to detect gas flow, but it need data collecting and processing unit. The thesis describes the software and hardware design of data collecting and processing system, and discusses how to calculate the phase shift from signal in strong noise background.By use of vibration differential equations of the measuring tube which based-on Euler beam theory, the outside vibration on CMF are analyzed. The conclusion is proved by the experiment of C.Clark and R.Cheesewright. In order to investigate the disturbance of outside vibration and to calculate the phase shift, Singular-Value-Decomposition(SVD) method based-on Cross-high cumulant is designed and emulated by Matlab. It is proved that the algorithm is highly effective to eliminate the correlative noise and band-limited Gauss white noise. The SVD method can obtain the phase shift from signal space.The hardware and software design focused on Digital Signal Processing (DSP)-TMS320LF2407A is made to apply the algorithm to the data collecting board. By use of signal generator, the capability of data collecting board to calculate the phase shift is validated, and it is shown that the detection can achieve the precision we expect. Then, a series of experiments are made and lots of valuable data are obtained.In the end of the thesis, some suggestions are proposed to improve the data collecting and processing system, and the experiment setup according to the experimental results.