| 摘要 |
A system for communicating numerical data over an UHF radio channel including a transmitter and receiver. The transmitter includes an UHF oscillator whose frequency is modulated by binary information elements from a coding device. The coding device includes a first coder for providing limited sum coding and a second coder coupled to the first coder for providing Walsh I coding. The excursion of the coded signals modulating the UHF oscillator is selected to obtain a radiating spectrum of the two-phase P.S.K. type with no spectral component at the carrier frequency and having quadrature components resulting from its timing. The receiver includes a coherent-phase demodulator and means for reconstituting a decoded signal for generating carrier and timing signals. |
