| 摘要 |
PURPOSE:To improve secrecy by dividing a signal band into (n) on a transmission side, and inverting or substituting signals corresponding to (m) out of the (n) zones and transmitting their total signal. CONSTITUTION:A signal in a frequency band (f0, f2) when applied to an input terminal 10 is divided into a signal (b) as a component (f0, f1) by a low-pass filter 15 and into a signal (c) as (f1, f2) by the adder in a circuit 18. The signal (b) has the spectrum inverted by a spectrum inverter 16, and the composite wave (e) of the inverted signal and the output (c) of the circuit 18 is obtained by an adder 17 and transmitted to a transmission line 1. Therefore, the signal is not shaped into the original spectrum even by spectrum inversion. |
