A novel (non sinusoidal) signal delay and attenuation measurement of long RF cables with variable insertion loss

This paper describes the use of a novel, non-sinusoidal pulse named ldquospeedy deliveryrdquo or ldquoSDrdquo to measure combined delay and attenuation. These delay measurements are obtained with precision not found using the conventional methods of time domain reflection (TDR) or vector network analyser analyses. The measurements accurately estimate the insertion loss through 200 feet of coax and two small magnetically coupled loops at varying separation distances in air, water, and seawater. The measurement method is time domain transmission (TDT) using the SD pulse as the test signal for improved resolution. The SD signal results are compared with the loss of a sinusoid chosen for having an ldquoequivalentrdquo frequency, ie. equal to the bandwidth of the ultra wide band (UWB) SD pulse. The leading edge of the SD pulse does not change shape or exhibit dispersion, which makes accurate measurements of delay or attenuation possible, even on long cables with insertion losses exceeding 60 dB.