| 摘要 |
PROBLEM TO BE SOLVED: To detect a reception electric field strength without converting a reception signal into an intermediate frequency signal. SOLUTION: An orthogonal demodulation section 6 demodulates a QAM (quadrature amplitude modulation) signal amplified by a high frequency amplifier section 5 to provide an output of I, Q signals. An electric field strength data storage section 10 stores measurement data in advance denoting a relation between the reception electric field strength and a level of demodulated signals (I, Q signals). An electric field strength arithmetic section 11 applies logarithmic transformation to the amplitude of the digitized I, Q signals by an A/D converter 8 and references the data stored in the electric field strength data storage section 10 to calculate the reception electric field strength. |
