| 摘要 |
PROBLEM TO BE SOLVED: To obtain an amplifier which has reduced number of defects of a gradient amplifier for nuclear spin tomograph by constituting it so that the switching behavior of a digital pulsewidth modulator simulates the switching behavior of an analog pulsewidth modulator. SOLUTION: This digital pulsewidth modulator includes modulator basic elements which include a counter 5, comparators 61, 62, etc., and a means which is connected behind the comparators 61, 62, etc., so as to generate a control signal from a binary signal. The counter 5 has an output terminal for outputting a negative counter state Z. The comparators 61, 62, etc., have an input terminal for inputting the negative counter state Z, another input terminal for inputting one of digital signals IN and N-IN, and output terminals for outputting binary signals as the result of a less-than comparison and the result of a greater-than comparison. Then this amplifier is so constituted that the switching behavior of the digital pulse-width modulator simulates the switching behavior of the analog pulse-width amplifier.
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