DTS L54 Series, Руководство пользователя, Страница: 8 / 103

DTS Broadcast PDH Microwave Digital Radio User Manual
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2.4 Basic Structure
A universal radio basic structure concept has been implemented for the L54 product line. A
radio terminal consists of three components: IDU, ODU and Antenna. A single coaxial cable is
required to interconnect the IDU with the ODU. This single cable feeds DC power to the ODU from
the IDU and supports bi-directional traffic, alarm and control signals.
This basic structure is used for the full frequency range from 1 to 23 GHz to maximize flexibility,
commonality of spare parts and interchangeability. This universal radio basic structure is illustrated in
Figure 2-3. The primary frequency dependent components are the antenna and several modules within
the ODU including the transmit hybrid, receive hybrid and diplexer. The IDU is frequency independent
and the ODU is capacity independent. The network management system supports digital microwave
radios of all bands. NMS interface and auxiliary data interfaces are available in the IDU to support
Network Management, Auxiliary Data Channels, 1+1 Protection Interface or other custom interfaces.
Figure 2-3 L54 Product Basic Structure
Tributary data and service channels, radio overhead and network management information at
the local terminal are fed to the IDU. The IDU DSP converts the tributary data to TTL level signals and
multiplexes them with the service channels onto an aggregate data stream. The IDU digital modem
modulates the aggregate signal to create an Intermediate Frequency (IF) signal. The IF signal is
superimposed with DC power and sent to the ODU on a coaxial cable. The ODU converts the IF signal
to a Radio Frequency (RF) signal to the antenna of the remote terminal. At the remote terminal ODU,
the received signal is converted back to an IF signal. The IF signal is fed through the coaxial cable to
the IDU, where it is demodulated and de-multiplexed into tributary data and the auxiliary service
channels. The link is full duplex (bi-directional), fully symmetrical and transparent to the data stream.