Agilent Technologies 34972A User Manual page 258

Chapter 7 Tutorial
System Cabling and Connections
• Cable Resistance – Varies with wire gauge size and cable length. Use
the largest gauge wire possible and try to keep the cable lengths as
short as possible to minimize the cable resistance. The following table
lists typical cable resistance for copper wire of several gauge sizes
(the temperature coefficient for copper wire is 0.35% per °C).
ft (2 conductors)
AWG at 25 °C
14 5 m
16 10 m
18 15 m
20 * 20 m
22 30 m
24 50 m
* Recommended wire size for the screw terminals on 34970A/34972A plug-in
modules.
• Cable Capacitance – Varies with the insulation type, cable length,
and cable shielding. Cables should be kept as short as possible to
minimize cable capacitance. In some cases, low-capacitance cable can
be used.
The table below lists typical cable specifications.
Cable Type Nominal Impedance
Twisted Pair 100 at 1 MHz
Shielded Twisted Pair at 1 MHz
Coaxial 50or 75 at 100 MHz
Twisted Pair Ribbon 100 at 1 MHz
258
Capacitance Attenuation
10 to 20 pF/ft Up to 1 dB/100 ft at 1 MHz
10 to 20 pF/ft Up to 1 dB/100 ft at 1 MHz
15 to 25 pF/ft Up to 6 dB/100 ft at 100 MHz
15 to 20 pF/ft Up to 1 dB/100 ft at 1 MHz