| 摘要 |
PROBLEM TO BE SOLVED: To accurately demodulate a received burst signal received with a small memory capacity and a small circuit scale. SOLUTION: A 90 deg. phase shifter 2 separates a signal from a local oscillator 1 into an in-phase component and a quadrature component. Mixers 3a, 3b multiplies each component with a received IF signal, which results in receiving quasi-synchronization detection. A/D converters 5a, 5b A/D converts the quasi- synchronization detection signal and integration circuit sections 6a, 6b integrates its preamble part. The integrated signal is latched by latch circuits 7a, 7b. A timing circuit 8 controls the latch timing. A power detection section 10 detects the power of the latched signal and a maximum value detection section 11 detects the maximum value of the power, then selectors 12a, 12b obtain a timing when the power is maximized. A phase θ is obtained from the arctangent of the maximum power and it is used for an initial value of a voltage controlled oscillator VCO of a demodulator 13. |
