Communication system with a limited communication area

A communication system, comprising:

• (a) a first communication area for receiving first communication signals;
• (b) a second communication area, spaced from said first communication area, for receiving second communication signals;
• (c) a communication shielding area, between said first communication area and said second communication area, for receiving a shielding signal wave and preventing interference between said first and second communication signals;
• (d) communication transmitting means for radiating a first modulated signal and a second modulated signal to said first communication area and said second communication area, said communication transmitting means producing a carrier wave having a fixed frequency and being modulated by said first communication signals and said second communication signals, said first and second communication signals having different content;
• (e) shielding transmitting means for transmitting said shielding signal wave into said communication shielding area;
• and
• (f) movable receiving means, movable across said first communication area, said communication shielding area and said second communication area and being tuned to said carrier wave fixed frequency, for receiving said first modulated signal, said shielding signal wave and said second modulated signal, respectively, and for demodulating said first modulated signal when in said first communication area and for demodulating said second modulated signal when in said second communication area, said movable receiving means receiving said shielding signal wave when in said shielding communication area at a receiving level equal to or greater than the receiving level of said first modulated signal and said second modulated signal.