| 摘要 |
A spread spectrum communication system includes a transmitter and a receiver, and an on-off keying signal is inputted to the transmitter. A carrier signal is modulated by the on-off keying signal, and a spread spectrum signal is produced by multiplying a modulated signal by a first PN code which is repetition of 3-bit data. The spread spectrum signal is transmitted through a transmission antenna. In the receiver, a second PN code which is repetition of 4-bit data larger than the first PN code by 1 bit is generated. Therefore, a phase of the second PN code becomes coincident with a phase of the first PN code every 12 bits. Then, a spread spectrum demodulation is performed by multiplying a received spread spectrum signal by the second PN code to reproduce the carrier signal being modulated by the on-off keying signal. The on-off keying signal is restored by envelope -detecting a reproduced carrier signal. |
