| 摘要 |
PURPOSE:To take a precise measurement even if a fluctuation signal varies greatly by detecting the flow state of fluid, etc., by detectors provided at an upstream and a downstream side, and measuring the flow velocity by using fluctuation signals outputted from both detectors. CONSTITUTION:The correlation type speedometer equipped with the detectors 1 and 2 at the upstream and downstream sides, amplifiers 3 and 4, and a multiplier 7 is provided with an upstream-side voltage divider 11 and a downstream-side voltage divider 20, an amplification factor switch 12, and an upstream-side comparator 14 and a downstream-side comparator 16. If the upstream-side input signal of the multiplier rises above a voltage corresponding to an upper-limit voltage, the voltage division ratios of the upstream and downstream voltage dividers are decreased to lower the upstream and downstream input signal voltages of the multiplier. When the upstream input signal of the multiplier falls below a voltage corresponding to a lower-limit voltage, the voltage division ratios of the upstream and downstream voltage dividers are decreased to raise the upstream and downstream input signal voltages of the multiplier so that the voltages inputted to the multiplier are within a permissible range even if the output signals of the detectors vary greatly. Consequently, fluctuation signals which vary greatly are measured precisely. |
