| 摘要 |
PURPOSE:To accurately measure a potential difference between two points of an oscilloscope specified on a time base by making a sequential comparison by using a register, a D/A converter, an analog comparator, etc., and converting a voltage to be measured into one-bit digital data. CONSTITUTION:When a measurement point signal of >=1 sweep is led, a comparator 2 compares an analog input passed through a buffer 1 with the bit converted voltage of a 1st measurement point from a control arithmetic circuit 5 through a D/A converter 3 and the result is stored in a D type FF 41. When the analog input is higher, the Q output of the FF 41 goes to 1 and a switch SW1 is turned on, so that 1 as the MSB set in a shifter 51 is fetched to a register 51. Then the outputs of the register 51 and shifter 54 are ORed and the result is stored in a register 53 and supplied to the converter 3 for next-bit comparison. Even when the input data is smaller, similar processing is performed and a 2nd measurement point is the same and the digital voltage difference between both measurement points which are converted into specified bit data by sequential comparison is accurately measured.
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