| 摘要 |
In some examples, there is described a measurement system, methods and other apparatus and devices used in measuring fluid, and for example fluid density. Some examples describe a system having a measurement cell (110) for fluid to be measured. The cell, together with the fluid to be measured, may have a particular frequency response characteristic within a band of frequencies. An excitation device (160) may also be used that is configured to communicate an excitation signal to the cell. Such an excitation signal can comprise a plurality of frequencies within a selected band, and that selected band may be based on the particular frequency response characteristic of the cell and fluid to be measured. Further, a response sensor may be used to obtain a spectral response from the measurement cell across some or all of the selected band. In some examples, in communication with the response sensor, a controller (300) can be configured to calculate a resonant frequency response characteristic of the cell and fluid based on some or all of the obtained spectral response, and calculate the density of fluid in the measurement cell based on the calculated resonant frequency response characteristic. |
