| 摘要 |
PURPOSE:To make it possible to measure the moving speed of a matter, by receiving scattered beam obtained by irradiating the moving matter to be measured with laser beam through parallelly arranged limited openings by a photoelectric converter element while removing a DC component to detect zero crossing. CONSTITUTION:Laser beam is outputted from a semiconductor laser beam source 10 to irradiate a matter 17 to be measured while generated scattered beam is received by photodiodes 19a-19e through limited openings 18a-18e to receive space integration. A noise component is removed by this space integration and the obtained signal is imparted, for example, to the input terminal 21a of a signal processing part 18. Signals having different wave forms but same modes are inputted to the other input terminals 21b-21e. Thereafter, a DC component is cut by a DC component removing circuit 27a to obtain signals each having a zero crossing point. These signals are applied to a Schmitt circuit and pulse signals outputted from monostable multiplier come to pulse signals corresponding to zero crossings. These signals are inputted to a counter to perform measurement. The sum total of the numbers of zero crossings is correlated to the speed of the moving matter to be measured and converted to a speed amount signal by a speed amount converting circuit 24 to be outputted from an output terminal 25. |
