| 摘要 |
PROBLEM TO BE SOLVED: To automatically improve the deterioration of receiving properties caused by the phase noise and the parasitic oscillation of a local oscillator by allowing an antenna to automatically judge the factor of the deterioration in the receiving properties. SOLUTION: A digital broadcast receiving apparatus 100 comprises a C/N value calculating means 12A, a phase noise quantity calculating means 12B, and a bit error rate measuring means 13A and in receiving, quadrature detection of a received signal transmitted from an antenna 1 into a baseband signal is performed. The average value of the amplitudes of this baseband signal in the radial direction of a phase mapping signal point is then measured to calculate a C/N value. The average value of the amplitudes of the baseband signal in the circumferential direction of the phase mapping signal point is then measured to calculate the phase noise quantity of the received signal and further, the bit error rate of a transport stream resulting from demodulating the baseband signal is measured. On the basis of these results, the factor of the deterioration in the receiving properties is judged and on the basis of this judged result, a predetermined countermeasure mode is set. COPYRIGHT: (C)2005,JPO&NCIPI |
