| 摘要 |
PROBLEM TO BE SOLVED: To vary the length of a pseudo noise signal according to the state of a transmission line. SOLUTION: A diffusion processing part 12 of a transmitting device 1 modulates the PN code supplied from a PN code generation part 11 to produce a diffusion signal based on the input data. Then the diffusion signal is sent to a receiving device 3 via a transmitter 14. A receiver 21 of the device 3 demodulates the received diffusion signal, and a correlation calculation part 22 calculates the correlation between the demodulated diffusion signal and the PN code that is generated at a PN code generation part 23. A chip error rate calculation part 26 calculates a chip error rate per frame based on the correlation calculated at the part 22. A code length selection part 24 selects the code length in response to the chip error rate calculated at the part 26. When the selected code length is different from the present code length, the former code length is supplied to the part 23 and also to the part 11 via a transmitter 27 and a receiver 13. Thus the code length is updated. |
