The characteristics of the two cables are compared with each other, and with some repre­sentative types of standard coaxial cabies.

5. 2. 3.1 Nickel-Clad Copper — Quartz — Stainless Steel Cable

With a 21-rfoot length of this cable, a determination of the attenuation characteristics versus frequency was made (see Figure 5-1). It is shown in this illustration that the cable starts to attenuate at approximately 200 kc/sec, and exhibits a 3 dB attenuation at a frequency of approxi­mately 1. 4 Mc/sec. The attenuation then falls with a continually increasing negative slope, and has an attenuation factor of 57 dB at a frequency of 100 Mc/sec.

The transient pulse characteristics of this cable were investigated by inserting a pulse with a 1 msec width at the sending end of the cable, and determining the rise time of the pulse at the receiving bnd of the cable. Figure 5-2 shows these response characteristics. Note that the rise time of the pulse at the receiving end of this cable is 0. 312 psec, with a sending end pulse rise time of 14 nsec (uncorrected)[6] or 7. 7 nsec (corrected). If the cable is considered a single time constant system, the upper 3 dB frequency is determined as

f = = Ml x 10+6 = L із Mc/SeC. .

7 r 031