ZHC939G FM Tunnel Broadcast Near-end Transmitter
1. Overview
The ZHC939G FM tunnel broadcast near-end transmitter is a front-end device that receives and processes the front-end signal in the tunnel broadcasting system, converts it into an optical signal and transmits it to the remote transmitter of the tunnel. It and the remote transmitter are the main transceiver equipment in the tunnel broadcasting system. They are connected by optical cables. Cooperating with leaky cables or transmitting antennas, it can effectively fill the coverage blind area and extend the coverage of the transmitting station. Mainly used in highway tunnels, underground parking lots, subway tunnels and station halls, civil defense facilities, schools, etc.
2. Features
This transmitter is distinguished from functional modules and can be divided into five parts: FM antenna reception and pre-amplification, FM broadcast signal digital processing unit, electro-optical conversion and optical signal transmission unit, remote monitoring unit, and emergency carrier insertion unit.
l FM antenna reception pre-amplification: frequency range: 87-108MHz, gain: ≥20dB.
l FM broadcast signal digital processing digital frequency selection, digital filtering (using FPGA+DDS digital filtering technology.
l The near-end machine with 4 optical ports can adopt various forms of networking structure, such as chain type, star type, tree type, ring, etc.
l The wireless link established by the channel 4G router and the monitoring center realize remote monitoring.
l In an emergency, all 16 output carriers can be used to broadcast emergency interrupt audio.
l Adopt modular design.
l The bidirectional optical channel can simultaneously transmit 16 FM carrier frequency signals.
l Realize remote monitoring.
l With optical bypass function.
l This machine is a near-end transmitter in the tunnel broadcast coverage system and must be used in conjunction with a remote transmitter including optical receivers and power amplifiers.
3. Diagram
4. Technical Specifications
Working frequency band |
87~108MHz |
21MHz |
Carrier number |
16 |
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Channel bandwidth |
150KHz, the lowest step can be set to 100KHz |
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Gain
(AGC off)
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Antenna input |
42dB±2dB (add LNA) |
N type connector |
Intermission |
5dB±2dB |
N type connector |
Gain adjustment range and step length |
0dB~50dB adjustable, 1dB stepping |
Remote/ Near-End |
Gain adjustment error (1dB) |
1-20dB |
≤±1.0dB |
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20-50dB |
≤±1.5dB |
Output power (maximum) |
-5dBm±1dB |
Multi-carrier total power |
Automatic level control range |
≥20dB |
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Automatic channel equalization range |
±15dB |
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Interrupt frequency setting range |
86～108MHz (4 digits after the decimal point) |
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Inter-modulation |
≤-55dB |
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Frequency stability |
0.05ppm |
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Time delay |
≤25us |
Customizable |
Delay compensation |
Time delay compensation range: 125μs
Delay compensation mode: automatic
Time delay adjustment accuracy: 1μs
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Spurious emission |
Spurious emission in effective working frequency band |
≤-60dBc |
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Outside the working frequency band |
9kHz~1GHz in band ≤-36dBm
1GHz~12.75GHz in band≤-36dBm
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SWR |
Input |
≤1.30 |
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Optical loop function |
Support |
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Optical transceiver alarm function |
Support |
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Number of optical ports |
REC support 4 ports |
Interface FC/UPC |
Optical module rate |
1.25Gb/s |
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Optical module type |
SFP |
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Networking function |
Star, chain, ring and hybrid networking, etc. |
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Software upgrade |
Support remote online upgrade, support any node upgrade, support version rollback. |
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4G router antenna interface |
SMA*2 |
SMA |
Operating Voltage |
220ACV±20%, 50Hz |
Aviation plug |
Operating Temperature |
-40℃~+55℃ |
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Working atmosphere |
70KPa~106KPa |
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Local and remote Ethernet RJ45 |
Can be used for local and remote communication |
RJ45 |
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