| 摘要 |
PROBLEM TO BE SOLVED: To swiftly generate waveform of a desired frequency when switching between internal synchronization and external synchronization by outputting the read-out clock of either of a phase-locked loop and an internal oscillation circuit to an waveform data read-out section in accordance with a switching command. SOLUTION: A control section 7 outputs a frequency setting signal from a frequency setting switch 5 to an internal oscillation circuit 21, and the internal oscillation circuit 21 oscillates an internal synchronization read-out clock n times the frequency setting signal. Meanwhile, an external synchronization signal generating circuit 22 generates a phase detection signal synchronized with the commercial frequency of a commercial power line, and a phase-locked loop circuit 23 oscillates an external synchronization read-out clock which is synchronized with the phase detection signal and has a frequency n times the phase detection signal. A switching circuit 24 selects either of the internal synchronization read-out clock and the external synchronization read-out clock in accordance with a switching signal from a change-over switch 6. This makes it possible to instantaneously generate waveform phase locked with external signals. |
