DATA TRANSMISSION INVESTIGATION

Abstract

Abstract : Results obtained in back-to-back white noise testing of the various modems are discussed. Problems of crosstalk and transmission levels encountered in the AN/TCC-7 white noise tests are also discussed. Controlled impulse noise tests were conducted. The results show that of the various modems tested thus far, the vsb modem is the most susceptible to impulse noise. The results are depicted in curves of bit error rate vs. rms signal to peak-to-peak noise ratio. A photograph of the controlled impulse used for the test is presented. A system for recording impulses encountered in field testing and how it may help in the study of data transmission is discussed. The amplitude and delay characteristics of the AN/VRC-12 radio set are presented in graphical form. Also presented is a tabulation of the modem bench tests conducted over the AN/VRC-12 showing that the radio set may possibly perform very well as a digital data transmission link. Noise quieting curves of the AN/TRC-24 radio set are discussed and the performance of the various modems over the radio set operating near and on the FM threshold is reported. The results of field cable testing of the modems are presented in tabulated form with a more detailed discussion of hi s and drop outs in this transmission link. (Author)