Coriolis type apparatus for measuring mass flow of a fluid stream

A Coriolis type apparatus for measuring mass flow of a fluid stream, comprising at least one flow conduit (14, 15) which is oscillated at a resonant frequency transverse to the direction of flow while said fluid flows therethrough, two sensors (27, 28) for generating analog signals corresponding to the motion of the flow conduit (14, 15), and signal processing means (30) for determining time difference between said analog signal, said signal processing means (30) including means (50, 51) for converting said analog signals into series of digital signals and means (55) to compute from said series of digital signals said time difference by using Fourier transformation. Each of the analog signals generated by the sensors (27, 28) is converted into a series of digital signals by an incremental type analog-digital converter (50, 51) having a comparator (42, 43), an up-down counter (44, 45) and a digital-analog converter (46, 47).