Chapter 2
Operation
Page 2-2
5/02/05
CM 100Base-T System User’s Manual
Transmitter Unit (TXU)
- accepts the modulated 70-MHz transmit signal from the
MOD and delivers it to the RF Distribution filter for output to the antenna.
Internal to the TXU, the signal goes through a double up-conversion process that uses the
first on-board local oscillator and RXU frequency synthesizer to provide the second local
oscillator. The resultant microwave frequency signal is further amplified and applied to
the TXU output.
Three output power configurations are available for CM6 and CM7/8 radios: standard
power (SP), high power (HP), and extended high power (DHP); two power
configurations for CM11: standard power (SP) and high power (HP). The HP and DHP
option provides 6 dB more output power for a given capacity and channel bandwidth.
DHP provides 9 dB more output power, up to the maximum hardware limit stated in
Table 1-C – the specification table. During severe fades the TXU Automatic Power
Control (APC) feature increases output power to maintain the RF link. See APC
discussion on Page 2-17.
Receive Function
Receiving starts with RF signal conversion to IF, de-multiplexing, signal processing and
conditioning, and output at the Access Panel. Receive signals enter the radio antenna and
proceeds through the radio modules as follows:
Receiver Unit (RXU) -
accepts the received RF signal from the RF Distribution filter
and delivers a 70-MHz signal to the DEMOD. Internal to the RXU, the signal goes
through a low noise pre-amplification stage and a downconversion process that uses a
frequency synthesizer to provide a local oscillator. The unit amplifies, filters, and applies
the resultant 70-MHz signal to the DEMOD.
Demodulator (DEMOD)
- receives a multi-level QAM signal centered at 70 MHz from
the RXU. Performs the complementary function to the MOD by removing the 70-MHz
carrier from the input and then outputs the recovered data directly to the demultiplexer
section of the MUX. An ATDE automatically equalizes channel distortions from multi-
path fading.
Demultiplexer (MUX module)
- the symbol stream enters from the DEMOD. The
DEMUX separates this signal into an NRZ data signal, four 64-kbps service channels,
two 64-kbps internal overhead channels, and with the WTU option–DS1/E1 and 9600 bps
signals. The data signal goes to the SYNDES module for signal decoding and
conditioning.
One of the two 64 kbps overhead channels handles inter-site communications and the
other is the Network Management data.
Desynchronizer (SYNDES module) -
receives the NRZ data signal from the MUX and
clocks these signals into an elastic buffer. A PLL provides a recovered smooth clock for
the output of the elastic buffer.
The resultant smoothed data and clock feed NRZ line decoder. Decoded 100Base-T data
signal goes to the outputs of the SYNDES and then to the Access Panel. WTU signals
also route to the Access Panel.
Service Channel (SCU)
- converts the four 64 kbps service channels to two voice
frequency and two data channels. All service channels route to the Access Panel for
customer connection.
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 ...