| 摘要 |
PROBLEM TO BE SOLVED: To reduce the compexity of a circuit by executing the generation of in-phase (I) and quadrature phase (Q) signals without based on the function of component having different phase and amplitude and without based on the common difference of different conduction line when executing the sampling of received signal on an intermediate frequency (IF) band. SOLUTION: This system is provided with a circuit for reducing the input signal into IF range having a central frequency fc2 and a band Bhz as a synchronizing detector for the RF input signal modulated through a digital system such as a quadrature amplitude modulated(QAM) and residual sideband(VSB) RF input signal and a converter circuit 50 for generating the next correspondent base band signal by sampling the IF signal. The IF signal is sampled at frequencies (fsA and fsB), the output is applied through a low-pass filter 53 to a sample/ hold circuit connected to an analog/digital(A/D) converter 52, the output of the A/D converter 52 is next applied to a Hilbert filter 328, the sampled signal is demodulated, and the base band signal is generated. |
