| 摘要 |
PROBLEM TO BE SOLVED: To improve phase angle determination in a portable radio communication terminal 10 for determining a symbol with respect to both the modulation signals ofπ/4 shift-QPSK and quaternary FSK, based on the phase angle of a wave detection signal. SOLUTION: A differentiator 21 differentiates the wave detection signal from a wave detector 19. A determination unit 22 determines whether a differentiation value exceeds a threshold or not, selects a senary→binary determination unit 30 when the determination is right, and selects a quaternary→binary determination unit 29 when the determination is wrong. The quaternary→binary determination unit 29 performs quaternary→binary determination like +3/4π→"01". +1/4π→"00", -1/4π→"10", -3/4π→"11". The senary→binary determination unit 30 performs senary→binary determination like +5/4π→"11". +3/4π→"01". +1/4π→"00", -1/4π→"10", -3/4π→"11", -5/4π→"01". COPYRIGHT: (C)2009,JPO&INPIT
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