| Coriolis mass flowmeter which can measure mass flow rate directly is currently one of the fastest growing flowmeters. In this thesis, advanced digital signal processing and digital signal processor (DSP) are applied to Coriolis mass flowmeter, to overcome the current limitations of signal processing methods used in this kind of flow meter. And the system software of digital transmitter is developed.For the single-phase flow measurement, the measurement error of the CMF's low flow rate is large so that the range is limited. Point against the above problems, this article combine the adaptive lattice notch filter and DTFT recursive algorithm with negative frequency modified , which can accurately track the signal frequency and calculate phase difference.The results of system tests show that the frequency accuracy is greater than 0.01%, the phase difference accuracy is greater than 0.05% in a wide range of [ 0.050,40]. Compare to previous methods, the speed of the proposed method's convergence process much faster, the amount of calculation is smaller and the system implementation is much easier.According to the characteristics of signals in the CMF's complex flow measurement, such as two-phase flow, batch material flow, signal model of time-varying through improving random walk model is established, and a new kind of digital signal processing algorithm which is composed of adaptive lattice notch filter and sliding DTFT (SDTFT ) recursive algorithm with negative frequency modified is presented. For the signal with small fluctuations, the calculation accuracy of this method is greater than other methods. For the jump signal, this method has a faster dynamic response, and can track the change of parameters timely. Furthermore, the above algorithm, which has a small amount of calculation, does well in anti-interference and will not overflow in fixed-point implementation, etc. So it will have a good prospect in Complex flow measurement.A digital Coriolis transmitter is developed with the core of TMS320F28335 DSP chip. In order to achieve the above-mentioned two kinds of algorithms in real time with highly precision, many measures are taken, in hardware design, e.g. selecting of high-quality capacitors, improving filter cutoff frequency, usingΣ-Δtype ADC, etc. In software development, e.g. using double-precision real variable type, improving sin / cos library function calculation accuracy, performing the second average to enhance the stability, achieving high precision pulse output with the module of ePWM, improving the system immediacy by using the DMA transmission ,etc. Also, the corresponding system software is designed and multi-functions of the instrument is well realize.Finally, System tests and experimental calibration are done to test the performance of the digital transmitter. For the steady single-phase flow measurement, the precision can reach to the degree of 0.1 and the range of measurement is wider, which are leading domestic and close to the global leader—Micro Motion in Coriolis flowmeter; For two phase flow, the transmitter can maintain the flow tube vibration, and be able to measure the mass flow. and the same situation, so the transmitter is stopped, beyond measure. To the same situation, the transmitter of TaiHang stops flight vibration and can not work. The results of experimental calibration show that the developed system has superior performance and the proposed algorithms are advanced, which have good prospects for industrialization.
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