| 摘要 |
PURPOSE:To obtain a peak value data having high reliability by stably discrimination each particle detection pulse of a particle detection signal with good accuracy, by digitizing a particle detection analogue signal by an A/D converter to store the same and applying comparing processing to the stored data to store the same as peak value data in the peak timing of the particle detection signal. CONSTITUTION:A particle detection signal is converted to a digital line corre sponding to the sampling clock of a clock circuit 14 by an A/D converter 11 and temporarily stored in data buffer 12. A subtractor 15 subtracts the preceding data stored in the buffer 12 from the data from the A/D converter 11 and the peak value data of the buffer 12 is stored in buffer 13 by the L-output of a comparator 16 when the operation result changed from a positive value to a negative one. A comparator 19 generates H-output when the operation one and, when the H-outputs of the comparators 16, 19 are succeeded for a definite time, a signal is outputted through a rising and falling time monitor circuit 17 and a particle pulse discrimination circuit 18 and the data of the buffer 13 is sent to CPU to calculate particle size distribution. |
