| 摘要 |
PURPOSE:To keep high accuracy for the frequency discrimination independently of the modulation system with respect to the frequency discriminator obtaining a frequency deviation of a reference carrier for the demodulation of a modulation wave based on a carrier frequency of an orthogonal amplitude modulation wave. CONSTITUTION:The discriminator is provided with a phase error detection means 11 in which coordinates id, qd and errors ie, qe with respect to coordinates of a substantial signal point are obtained from coordinates of the signal point representing a symbol on a signal space as to each symbol and a phase error DELTAthetaof a demodulation use reference carrier signal is obtained based on equation of DELTAtheta=idXqe--ieXqd, a frequency deviation detection means 13 which differentiates the phase error DELTAtheta by a time for a timing for digital conversion to obtain a frequency deviation of the reference carrier signal with respect to the carrier signal and with a limit means 15 limiting the frequency deviation obtained by the frequency deviation detection means 13 within an upper limit in response to the accuracy of the reference carrier signal. |
