| 摘要 |
<p>PURPOSE:To enhance the secrecy by outputting an initial value, corresponding to the length of M code (longest linear code series), arbitrarily from an M code initial value generating circuit and varying the phase modulation pattern of a transmission wave thereby spreading the transmission wave over a wider band. CONSTITUTION:A transmission timing generating section 5 receives a signal from a counter 4 and generates a gate corresponding to the transmission pulse width. An code length data of M code is fed through a bus transceiver 1 to an M code coefficient latch 6 thence to an M code generating section 7. Every time when an M code modification signal is received, an M code initial value generating section 9 delivers the initial value of M code, corresponding to the code length, arbitrarily to an M code generating section 7. Since the phase modulation pattern of transmission wave is varied as compared with the case where the initial value is constant, the spectral pattern of transmission wave is varied and the secrecy is enhanced.</p> |
