Full Duplex Transmission Operation of a 2.45-GHz Asynchronous Spread Spectrum Modem Using a SAW Convolver

Kazuo Tsubouchi, Hiroyuki Nakase, Akihiko Namba, Kazuya Masu

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


An asynchronous spread spectrum (SS) modem in the 2.45-GHz band has been implemented using an efficient ZnO-SiO2-Si surface acoustic wave (SAW) convolver. The design of the highly efficient SAW convolver was developed at Tohoku University and commercially available devices have been manufactured by Clarion Co., Japan. The modem can operate under full duplex transmission in the same frequency range of the 2.45-GHz SS band. The SS modem 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 MSequences of a 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. We have experimentally confirmed a sufficient self-jamming rejection capability: a bit error rate of 10”6 is observed at -78.3 dB of a desired to undesired signal ratio using an artificial transmission line.

Original languageEnglish
Pages (from-to)478-482
Number of pages5
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Issue number5
Publication statusPublished - 1993 Sep
Externally publishedYes

ASJC Scopus subject areas

  • Instrumentation
  • Acoustics and Ultrasonics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Full Duplex Transmission Operation of a 2.45-GHz Asynchronous Spread Spectrum Modem Using a SAW Convolver'. Together they form a unique fingerprint.

Cite this