To provide a frequency measuring apparatus in which a frequency can be measured in real time by a digital processing operation.
A signal conversion part 21 comprises an A/D converter and an orthogonal demodulator, it converts a signal S to be measured into baseband digital orthogonal signals I, Q whose phases are at right angles to each other, and it outputs the orthogonal signals. A phase detection part 31 finds an initial phase value s and a finish phase value e on the basis of the digital orthogonal signals to be output from the signal conversion part 21 at a prescribed measurement start timing and at a prescribed measurement finish timing. A cycle slip detection means 32 monitors the digital orthogonal signals to be output from the signal conversion part 21 in a period from the measurement start timing up to the measurement finish timing, and it detects the existence and the number N of cycle slips. A computing means 33 calculates the frequency fx of the signal S, to be measured, on the basis of the initial phase value s, the finish phase value e, the number N of the cycle slips, a frequency conversion amount in the signal conversion part 21 and the measuring time T.
JPS6065681 | [Title of the device] Frequency discriminator circuit |
JP4242550 | Phase fluctuation detector |
JP6551879 | Detection sensor |
MATSUDA TOSHIYUKI
HASHIMOTO YUICHIRO
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