An Experimental 224 Mb/s Digital Repeatered Line

Abstract

An experimental digital repeatered line has been developed which transmits information at a rate of 224 Mb/8 as part of an experimental highspeed digital transmission system. The PCM terminals and time division multiplex portions were described by J. S. Mayo and others in the November 1965 issue of the Bell System Technical Journal. The repeatered line is described in this paper. The performance of this line is shown to be suitable for coast‐to‐coast operation. The line utilizes 0.270‐inch copper coaxial transmission lines and regenerative repeaters at one‐mile intervals. Ten repeaters have been operated in tandem to form ten miles of repeatered line. Each repeater uses 25 transistors, most of them a new germanium design with a cutoff frequency, ft, of 4 GHz. Esaki diodes provide the decision thresholds for the regeneration. Power to the repeaters is supplied by dc over the center coaxial conductor. The pulse transmission code is paired selected ternary (PST).

An Experimental 560 Mbits/s Repeater with Integrated Circuits

“…Starting point for dhensioning is the condition for quasi static phase error. Generally considered to be acceptable with respect to loss in signal to noise ratio is a quasi static phase error of about 0.1 radian [15]. This phase error is a result of the following imperfections: 1) drift of the quiescent VCO (voltage-controlled-oscillator) frequency from the digit frequency.…”

Analysis of an adjustable multipath network for use in building out transmission-line skin-effect losses

“…It is well known that the insertion-loss characteristic of a high-frequency coaxial transmission line with attenuation due to skin effect is of the form [4], [5] C(S) = e -STe-1kJS . (1) The first factor of the expression corresponds to a pure delay, whose exact value is of little concern in waveform transmission.…”

“…In the case of high-speed PCM baseband transmission systems [5], the timing circuit seeks the pulse peak and locks onto it, while the automatic gain control (AGC) circuit automatically adjusts the peak amplitude to a nominal (unity) value. To explore the application of a multipath adjustable LB0 within such a system, the simulation scheme of Fig.…”

Synchronizing Digital Networks

“…One satisfactory way to treat buffer overflow is to let bi«o of (1) change during time interAals when the integral would otherwise cause (14) In exploring the effect of buffer overload it is sufficient to consider a circuit element consisting of an inductor and two bias currents. For simplicity we will assume that these bias currents are equal and opposite, with magnitudes lo, as shown in Fig.…”