| 摘要 |
A spread spectrum communications system for use over a communication channel, including a transmitter-generic- chip-code generator (101), a transmitter-message-chip- code generator (102), an EXCLUSIVE-OR gate(103), a combiner (104), a transmitter (107), a receiver-generic- chip-code generator (121), a receiver-generic mixer (123), a generic-bandpass filter (125), a receiver- message-chip-code generator (122), a receiver-message mixer (124), a message-bandpass filter (126), and a synchronous detector (139). The transmitter-generic- chip-code generator (101) generates a generic-chip-code signal and the transmitter-message-chip-code generator (102) generates a message-chip-code signal. The EXCLUSIVE-OR gate (103) spread-spectrum process message data with the message-chip-code signal to generate a spread-spectrum signal. The transmitter (107) transmits the combined generic-chip-code signal and spread-spectrum signal, on a carrier signal (108) over the communications channel as a spread-spectrum-communications signal. The receiver-generic-chip-code generator (121) generates a replica of the generic-chip-code signal. The generic mixer (123) recovers the carrier signal from the spread- spectrum-communications signal. The receiver-message- chip-code generator (122) generates a replica of the message-chip-code signal. The receiver-message mixer (124) despreads the spread-spectrum-communications signal as a modulated-data signal. The tracking and acquisition circuit (121) uses the recovered carrier signal for synchronizing the replicas of the generic-chip-code signal to the recovered carrier signal. The synchronous detector (139) synchronously demodulates the modulated- data signal as received data.
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