DH437-R 4
2. Product Description.
The DH437-R is an FPGA based Digital Fiber Optic Remote Unit that transmit in the Downlink frequencies of
470-488MHz and receives in the Uplink frequencies 470-488MHz for United States.
This Remote Unit extends the radio coverage into areas inside the Base Station range where propagation losses
prevent reliable communication.
The DH437-R is fed by fiber via a Digital Master, the DH400-M. The DH400-M is connected directly to the B|ase
Station with no radiating elements.
The Master Unit provides the wired interface to the Base Station.
The DH437-R Remote Unit is the device where the service antennas are connected. Each DH437-R has dual
hardware, so it works as two identical and independent Remote Units integrated into one box. Each DH437-R
has two DL outputs and two UL inputs one per each internal Remote Unit.
The physical connection between the Master Unit and the Remote Unit is SM Fiber Optic cord. Each Remote
unit inside the DH437-R uses a separate fiber.
The Master Unit receives the DL input signal from a direct connection of Base Station, after that, it is sent though
a digital link to the Remote Unit. The Remote Unit the data is converted back to RF, amplified and radiated to
the Service antennas.
At the Uplink Input port, the Remote Unit receives the UL signal. The UL input signal comes from the Service
antennas, after that, this signal is digitally converted from RF to optical signal, and sent over the fiber. This signal
in the FO cord is captured by the Master Unit, re-converted from Optical to RF and sent back to the Base Station
though a direct connection.
The optical link allows the system to cover places which are far away from Base Station with fewer losses.
This DAS System is capable of handling 24 filters in uplink and 24 filters in downlink. The center frequency of
each one of the 24 filters can be tuned via a software interface.
The intermediate filtering of this equipment is performed by using FPGA based Digital Signal Processing that,
among many, has the following features:
- High Selectivity vs Low Delay performance selection.
- AGC per channel and per time slot.
- Squelch per channel and per time slot.
- Integrated Spectrum Analyzer.
Both Master Units and Remotes has the same a heavy duty IP67/NEMA4X cabinet for outdoor usage, it is
designed to be wall or pole mounted..
