Asynchronous transmission with strong spectral spread
Abstract
Resistance to signal detection and interception and resistance to interference and mixing are advantages of spread spectrum transmission in military communications. The construction of the emitter and receiver permitted testing an asynchronous radio link with a digitalization of speech by delta code, and also facilitated the obtaining of measurements. Spectrum spreading was achieved on a 80 MHz band by means of pseudo-random sequences coded in binary orthogonal keying using P.S.K. or M.S.K. modulation. Demodulation at reception was achieved in an asynchronous mode by a double piezoelectric surface acoustic wave convolutor operating at a frequency on the order of 400 MHz. Each convolutor was fed, partly by the signal received, and partly by a replica of the signal expected, at the same frequency, and with the same code inversed in time.
- Publication:
-
In AGARD Propagation Influences on Digital Transmission Systems: Probl. and Solu. 14 p (SEE N85-19269 10-32
- Pub Date:
- October 1984
- Bibcode:
- 1984pidt.agarU....S
- Keywords:
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- Multipath Transmission;
- Signal Processing;
- Spread Spectrum Transmission;
- Synchronism;
- Carrier Frequencies;
- Countermeasures;
- Decoding;
- Perturbation Theory;
- Specular Reflection;
- Surface Acoustic Wave Devices;
- Wave Reflection;
- Communications and Radar