| 摘要 |
PURPOSE:To simplify circuit constitution and to reduce cost by obtaining an addition signal with a second carrier setting a 1st-order modulated wave signal modulated by a first carrier and an information signal as an input signal, and spreading it by a spread code signal. CONSTITUTION:Information data d(t) is supplied from the input terminal In1 of a modulation part 10 to a multiplier 2 via an LPF2, and it is multiplied by the first carrier, and the 1st-order modulation signal (2-phase PSK modulation signal) is generated, and it is supplied to an adder 6. Also, the second carrier is supplied from the input terminal In3 to the adder 5, and addition on the 2-phase PSK signal is performed, then, it is supplied to a multiplier 3. A spread code P(t) generated at a spread code generation circuit 11 is supplied to the multiplier 3, and the multiplication(spread spectrum) by an image addition signal is performed by the multiplier. Thus, since a modulated spread code signal to be used in inverse spread is generated at the time of modulation and it is sent by frequency-inserting between spectra of spread spectrum signals, it is possible to make a clock regeneration circuit, a pull-in circuit and a synchronism holding circuit consisting of a loop, and the spread code generation circuit unnecessary. |
