Chapter 1
General Information
Page 1-8
8/12/03
CM7/8 100Base-T System User’s Manual
Transmission Engineering
RF channel separation, radio system gain, and interference considerations may affect the
performance of the radio.
Channel Separation
Typically, at all sites, radio frequencies should be grouped such that each radio
transmitter frequency is above the radio receiver frequency. The most common T/R
frequency separations on a common antenna (same polarization) are 490 and 500 MHz.
System Gain
The radio system gain is the transmitter power in dBm minus the receiver sensitivity or
threshold in dBm for a 10
-6
or 10
-3
BER. For example, the maximum transmitter power is
+31.0 dBm, and the typical receiver threshold at 10
-3
is -70.5 dBm. Therefore, the typical
system gain at 10
-3
is +31.0 - (-70.5) = 101.5 dB.
Interference
The CM7/8 receivers have substantially higher interference immunity than FDM/FM
receivers. Interference in an analog system shows up in the voice channels in direct
proportion to the level of the interference relative to the message carrier. In a digital
radio, like the CM7/8, interference only becomes apparent when it is of sufficient level
such that the T/I ratio of the digital receiver has been violated. Appendix A illustrates and
defines T/I ratio.
Transmission engineering considerations for hub operations, two-frequency plan
repeaters, cross-polarized operation and intersystem coordination must take into account
the differential fading that is quite likely to occur between the desired carrier and the
interference.
SP Section
Access Panel
SP Power Supply Unit (SP PSU)
Alarm and Control Unit (ACU)
Modulator (MOD)
Demodulator (DEMOD)
Multiplexer (MUX)
Synchronizer/Desynchronizer (SYNDES)
Service Channel Unit (SCU, optional)
Orderwire Unit (OWU, optional)
Wayside Traffic Unit (WTU, optional)
Network Management Unit (NMU, optional)
Table 1-B. CM7/8 100Base-T Radio Sections and Modules
(Continued)
Section
Module
Summary of Contents for CM7
Page 2: ......
Page 4: ...Page iv 5 04 05 CM7 8 100Base T System User s Manual ...
Page 16: ...Glossary Page xvi CM System Users Manual X Y Z ...
Page 24: ...Microwave Networks CM7 8 100Base T System User s Manual Pagexxiv ...
Page 62: ...Chapter 2 Operation Page 2 18 5 02 05 CM 100Base T System User s Manual ...
Page 64: ...Chapter 3 Module Descriptions Page 3 2 CM7 8 100Base T ...
Page 88: ...Section 3 3 Transmitter Unit Page 3 3 6 CM7 8 System User s Manual ...
Page 96: ...Section 3 5 RF Power Supply Unit Page 3 5 4 CM System User s Manual ...
Page 100: ...Section 3 6 SP Power Supply Unit Page 3 6 4 CM System User s Manual ...
Page 106: ...Section 3 7 Alarm and Control Unit Page 3 7 6 11 18 03 CM 100Base T System User s Manual ...
Page 124: ...Section 3 11 SYNDES Page 3 11 6 CM System User s Manual ...
Page 130: ...Section 3 12 SCU Page 3 12 6 11 18 03 CM 100Base T System User s Manual ...
Page 138: ...Section 3 13 OWU Page 3 13 8 CM System User s Manual ...
Page 150: ...Section 3 15 NMU Page 3 15 6 CM System User s Manual ...
Page 192: ...Chapter 5 Verification Page 5 20 CM System User s Manual ...
Page 194: ...Chapter 6 Maintenance Page 6 2 7 23 03 CM 100Base T System User s Manual ...
Page 224: ...Chapter 6 Maintenance Page 6 32 7 23 03 CM 100Base T System User s Manual ...
Page 226: ...Site Engineering Page 2 CM System User s Manual ...
Page 230: ...Appendix A T I Curves Page A 4 CM7 8 100Base T System User s Manual ...
Page 267: ...Microwave Networks CM System User s Manual PageB 37 ...
Page 268: ...Appendix B QuikLink Page B 38 CM System User s Manual ...
Page 282: ...Appendix D Alarm Codes Page D 6 5 02 05 CM 100Base T System User s Manual ...
Page 290: ...Appendix E Setting Frequency Page E 8 CM7 8 System User s Manual ...
Page 312: ...CM7 8 100Base T System User s Manual Page I 4 Microwave Networks ...