Title :
Full duplex transmission operation of a 2.45-GHz asynchronous spread spectrum using a SAN convolver
Author :
Tsubouchi, Kazuo ; Nakase, Hiroyuki ; Namba, Akihiko ; Masu, Kazuya
Author_Institution :
Res. Inst. of Electr. Commun., Tohoku Univ., Sendai, Japan
Abstract :
An asynchronous spread spectrum (SS) modem in the 2.45-GHz band has been implemented using an efficient ZnO-SiO/sub 2/-Si surface acoustic wave (SAW) convolver. The modem, which can operate under full duplex transmission is based on a direct-sequence/code-shift-keying (DS/CSK) method for the modulation. Pseudonoise (PN) codes are chosen from a preferred pair of m-sequences of period 127, and the code rate is 14 MHz. The demodulation is carried out asynchronously, utilizing the coherent correlation characteristics of the SAW convolver. The main interference caused by a transmitted signal in the modem itself is effectively reduced by an RF isolator and the SS process gain. Adequate self-jamming rejection capability has been confirmed; a bit error rate of 10/sup -6/ is observed at -78.3 dB of a desired-to-undesired-signal ratio using an artificial transmission line.<>
Keywords :
microwave links; modems; signal processing equipment; spread spectrum communication; surface acoustic wave devices; 14 MHz; BER; PN codes; RF isolator; SAN convolver; ZnO-SiO/sub 2/-Si; asynchronous spread spectrum; bit error rate; code-shift-keying; coherent correlation characteristics; demodulation; direct-sequence; full duplex transmission; m-sequences; modulation; pseudonoise codes; self-jamming rejection capability; surface acoustic wave; Acoustic waves; Convolvers; Demodulation; Modems; Modulation coding; RF signals; Radiofrequency interference; Signal processing; Spread spectrum communication; Surface acoustic waves;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
