| 摘要 |
PURPOSE: A carrier tracking apparatus in a wireless transmitter apparatus is provided, which tracks a carrier during recovering data modulated by a DBPSK(Differential Binary Phase Shift Keying) method, and compensates for a phase difference automatically according to the tracked data. CONSTITUTION: The carrier tracking apparatus of a DBPKS wireless transmitter apparatus comprises a channel signal classification part converting a signal modulated by a DBPSK method into an intermediate frequency, and classifies it into an I-channel(In-phase channel) signal and a Q-channel(Quadrature-phase channel) signal. An I-channel signal integrator part(26,27,35) extracts a base band signal by synthesizing the I-channel signal and an oscillation frequency, and integrates the extracted signal during one symbol duration and then outputs it to a DBPSK demodulator(100). A phase modulator generates a 90 deg.-phase shifted frequency of the oscillation frequency. A Q-channel signal integrator part(28,29,30,36) extracts a base band signal by synthesizing the Q-channel signal and an output frequency of the phase modulator, and integrates the extracted signal during one symbol duration and then outputs it to the DBPSK demodulator. An automatic frequency control part generates an automatic frequency control signal from a phase difference of temporal change of the I-channel signal and the Q-channel signal and the demodulated data. A converter converts the automatic frequency control signal into a DC voltage. And a voltage controlled oscillator(VCO) outputs an oscillation frequency to the I-channel integrator part and the phase modulator by converting the oscillation frequency according to an output of the converter.
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