| 摘要 |
PURPOSE: To expand/contract the waveform arbitrarily by providing a PLL circuit for varying the oscillation frequency of a source oscillation circuit continuously thereby varying the sampling frequency continuously. CONSTITUTION: Oscillation of a source oscillation circuit 2 is varied through a variable PLL circuit 9 and subjected to frequency division through a variable frequency division circuit 10 thus varying the sampling frequency fs over a wide range. Frequency variable range of the PLL circuit 9 is controlled based on a frequency set data 1a delivered from a sample control section 1. A switching signal 1b for one frequency division circuit 10 is also delivered from the control section 1 depending on the sampling frequency. Since a continuously varied frequency from the variable PLL circuit 9 is divided by an integer through the frequency division circuit 10, the output frequency can be varied continuously over a wide range. In case of a digital oscilloscope, a period of waveform can be displayed just on one screen by varying the sampling frequency through variable operation. |
