| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve a problem of a distance between communication stations by controlling a data rate of a transmission code at a transmitter side depending on a value of a carrier C so as to change a gain when received C/N is changed thereby keeping a prescribed S/N at a receiver side. SOLUTION: Received data sent from a transmitter 35 via an antenna 36 at the receiver side are received by an antenna 37. The signal is frequency- converted by a receiver 38, and the result is fed to a spread spectrum demodulator 39, in which the frequency and the phase of a spread code at the transmitter side are multiplied with those of an inverse spread code 40 and the spread code is demodulated. The demodulated signal is given an image decoder 41, where the signal is decoded into an original image signal and it is displayed on a monitor 42. On the other hand, an S/N detector 43 detects the C/N of the received signal, and a transmitter 44 sends the signal to a transmitter side by an antenna 45. The signal is received via an antenna 46 and a receiver 47. The data rate of the C/N signal is revised even in the case of decoding by the image decoder 41 in matching with revision of the data rate of the image coder 32. Then the receiver side keeps a prescribed S/N.</p> |
