| 摘要 |
PURPOSE:To attain the detection of a positive correlation output by detecting the correlation between a preamble and an PN code outputted from a reference PN code generator by a SAW convolver and applying AND processing to substantially extinguish a pseudo correlation output. CONSTITUTION:A received spread spectrum signal is subject to RF amplification and frequency conversion, becomes an intermediate frequency signal, amplified by an intermediate frequency amplifier 1 and frequencyconverted by a frequency mixer 5 and fed to one input terminal of the SAW convolver 7. A reference PN code from a reference PN code generator 8 and an output of an oscillator 9 are fed to a mixer 10 and its output is fed to the other input terminal of the convolver 7. The correlating output detected by the convolver 7 is subjected to undesired signal rejection by a band pass filter 11, detected by an envelope detector 12 and fed to an AND gate 14 via a waveform rectifier 13. an effective range decision pulse from the reference PN code generator control circuit 15 is sent and a positive signal is obtained from the gate 14. |
