| 摘要 |
PURPOSE: To reduce fluctuation due to the elapse of time by providing an IQ arithmetic means, a phase arithmetic means, a differentiation arithmetic means, and a shift quantity arithmetic means which calculates a peak value on the positive side and the one on the negative side of frequency shift from a modulated frequency. CONSTITUTION: An FM input signal is inputted to a Hilbert transformation part 9, and its common mode component I and orthogonal component Q are calculated, and they are called a pair of Hilbert transformation. The pairs of transformation I, Q are inputted to a phase arithmetic part 10, and an instantaneous phase is calculated, and the time series data of instantaneous phase is inputted to a differentiation arithmetic part 11, then, the modulated frequency fa (t) is calculated. The time series data of modulated frequency fa (t) is inputted to and corrected by a carrier frequency error elimination part 12. The modulated frequency fa (t) is inputted to a BPF 14 via a de-emphasis part 13, and its noise component is eliminated, and a frequency of the high end is also limited, and it is inputted to a shift quantity arithmetic part 15. The arithmetic part 15 calculates the peak value P on the positive side and the peak value P on the negative side of frequency shift, and data with respect to them are inputted to a display device 16, then, they are displayed on a screen. |
