Patent ID: 7680225

Claim:
A receiving apparatus, comprising: demodulation means for demodulating a reception signal to a signal on a real axis and a signal on an imaginary axis; carrier-to-noise (C/N) ratio calculation means for calculating a C/N ratio with amplitudes in an amplitude direction of signal points of the reception signal demodulated by said demodulation means and a C/N ratio with amplitudes in a phase direction of the signal points of the reception signal demodulated by said demodulation means; phase noise detection means for detecting phase noise based on the C/N ratio calculated with the amplitudes in the amplitude direction and the C/N ratio calculated with the amplitudes in the phase direction; indication means for indicating the C/N ratios calculated by said C/N ratio calculation means; a display unit to display the phase noise detected by the phase noise detection means based on the C/N ratio calculated with the amplitudes in the amplitude direction and the C/N ratio calculated with the amplitudes in the phase direction as a numeric value; and an alarm indicator which provides an indication to a user when the phase noise detected based on the C/N ratio calculated with the amplitudes in the amplitude direction and the C/N ratio calculated with the amplitudes in the phase direction is equal to or larger than a predetermine value.