| 摘要 |
PURPOSE:To simplify the circuit without using spread codes like PN codes by spreading the output signal, which is obtained by linearly modulating a carrier by an information signal, with a spread signal consisting of an analog signal having a prescribed frequency and inversely spreading and demodulating a reception signal by an inverse spread signal. CONSTITUTION:The information signal is applied to a linear modulation circuit 15 through an input terminal 23. Meanwhile, the carrier signal from a VCO 16 is inputted to the circuit 15 and a programmable divider 17. The carrier signal inputted to the divider 17 has the frequency divided by a variable frequency division ratio, and the output signal has the phase compared with a reference signal by a phase comparator 19, and the output signal is inputted to the VCO 16 as a control signal through an LPF 20. The carrier signal is modulated in the circuit 15 by the information signal to generate a modulated signal, and this signal is inputted to a multiplier 22 and is multiplied by the analog sine wave signal from an oscillator 21, and the spread spectrum signal is transmitted from an antenna. Meanwhile, the reception signal is inversely spread and demodulated in a spectrum inverse spread circuit by the inverse spread signal to obtain the information signal. |
