| 摘要 |
PURPOSE: To obtain the system where correction of the stability of synchronization acquisition in deteriorated channel quality and of Doppler shift is simplified in the mobile communication equipment employing the spread spectrum system. CONSTITUTION: A transmitter is made up of a primary data modulator 6, a secondary spread spectrum modulator 7, and a preamble generator 5, the preamble generator 5 generates consecutive data of '1' or '0' for a preamble period, generates a non-modulation wave for the preamble period by giving the data to the primary modulator 6. The non-modulation data only for the preamble period are given to the spread spectrum modulator 7, in which spread spectrum modulation is conducted to improve the reception S/N by minimizing a demodulation signal band at synchronization acquisition. |
