| 摘要 |
<p>PROBLEM TO BE SOLVED: To demodulate a QPSK modulation signal without the use of a mixer or 90-degree phase shifter. SOLUTION: A QPSK modulation signal is sampling-processed by a clock CK1, fetched in a CCD delay 2, and transferred by a clock CK1. A difference signal between cells C0 and C2 of the CCD delay 2 is sampled-and-held by a clock CK2, and outputted as a signal I(t), and a difference signal between cells C1 and C3 is sampled-and-held by the clock CK2, and outputted as a signal Q(t). The clock CK1 is generated by a voltage controlled oscillator according to the difference of the absolute value of each signal I(t) and Q(t). The clock CK2 is obtained by 4 frequency-dividing the clock CK1.</p> |
