| 摘要 |
PROBLEM TO BE SOLVED: To provide a DDS capable of increasing greatly the number of outputtable frequencies, while maintaining phase consistency, and an NMR device using it. SOLUTION: This direct digital synthesizer having a phase accumulation part and a phase/amplitude conversion part is equipped with a plurality of phase accumulators 21-1 to 21-N operated by a fixed phase increment of the multiplier of two, a controller 22 for outputting each bit of a frequency set value FTW as a control signal, a plurality of switches 23-1 to 23-N for outputting an output from each phase accumulator 21 when the control signal from the controller 22 is 1 and outputting 0 when the control signal from the controller 22 is 0, and an adder 24 for adding each output from the plurality of switches 23. COPYRIGHT: (C)2009,JPO&INPIT
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