1055478-1 TE Connectivity, 1055478-1 Datasheet - Page 117

• Manufacturer Part Number: 1055478-1
• Description: Connector Accessories Cable Bender
• Manufacturer: TE Connectivity
• Type: Benderr

Specifications of 1055478-1

• Lead Free Status / RoHS Status: RoHS Not Applicable

Fast rise times and short pulse widths require high frequen-
cy components.
Two frequent causes of digital signal degradation can be
(1) high capacitance of the transmission line and (2)
impedance mismatches of connector transmission line or
I/0 devices. Selection of an impedance-matched connec-
tor on a digital line, especially if short cable assemblies are
used, can be as important as connector selection for an RF
modulated line. Reflected pulses out of phase with the
original pulse can cause false signals or high error
rates in a digital system.
Since pulses with fast rise times are necessary in high-
speed computers, any circuit element which could reduce
or attenuate high frequency response is undesirable.
Catalog 1308940
Revised 5-03
www.tycoelectronics.com
1
7
5
Development of a Square Wave
3
S5
Dimensions are in inches and
millimeters unless otherwise
specified. Values in brackets
are metric equivalents.
S3
Figure 12
RF Connectors
Appendix A - Theory and Application
A
B
C
S3=1+3
S7=1+3+5+7
S5=1+3+5
Dimensions are shown for
reference purposes only.
Specifications subject
to change.
Signal Integrity and Propagation
To explain how to maintain signal integrity, it is necessary to
review how the signal is configured in a cable and how it
propagates. Ignoring digital signals for this discussion we
will identify the issues that deal with the integrity of a sine
wave. Consider a coaxial cable consisting of an inner con-
ductor surrounded by a dielectric material and then an
outer conductor (See Figure 13). The outer conductor may
be a braid, a foil, or a solid metal.
An electromagnetic wave traveling in a coaxial cable pro-
duces an electric and a magnetic field between the inner
conductor and the outer conductor (Figure 14). The electric
(E field) is radial and varies in time. An alternating current
flows along the inner conductor and the outer conductor. An
oscillating magnetic field (H field) circles the inner conductor.
The alternating current on a conductor is not spread through-
out the conductor but is strongest at the surface and decays
exponentially at points further into the conductor. This is
called the skin effect. At a frequency of 1MHz, three skin
depths is 0.0078” (95% of the current is within three skin
depths of the surface) and at 10GHz three skin depths is
0.00078”. As a result, the current is on the outer surface of
the inner conductor and the inner surface of the outer con-
ductor over the entire range of interest for most RF systems.
The dimensions and material beyond several skin depths
have no effect on the wave; gold plated plastic will propagate
as well as gold plated copper at sufficiently high frequencies.
(Continued)
belonging to the principal mode in a coaxial line.
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d
Dielectric
Material
Electric field (E) and magnetic field (H)
Outer
Conductor
V
Diagram of a Cable
Figure 13
Figure 14
E
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Center
Conductor
H
D
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7