1. Overview
ZHC5G series FM stereo broadcast transmitter (exciter) is an outstanding software radio product; it is designed with high reliability concept and has unparalleled performance indicators.
This transmitter uses a new large-scale field-programmable gate array (FPGA) and direct digital frequency synthesis (DDS) technology up to 5G, which has achieved the highest technical specifications in the industry so far, it’s providing listeners with CD-like sound quality.
The transmitter consists of audio interface unit, digital processing and FM modulation unit, radio frequency power amplifier unit, human-machine interface unit, communication interface unit, clock synchronization unit and power supply unit. The transmitter is installed in one 19-inch 2U standard case, and all input and output signals are led out from the rear panel.
2. Technical characteristics and principle block diagram
Product technology has the following technical features:
• Full process digital processing to achieve a perfect auditory effect of CD-like sound quality
• Full-scale digital processing with large-scale field-programmable gate array (FPGA) technology
• Direct digital frequency synthesis (DDS) technology at speeds up to 5G to peak transmitter specifications
• High reliability microprocessor (ARM) technology as the primary controller
• Support for multiple audio source inputs (transmitters can be automatically selected by priority):
◆ Two AES/EBU digital audio signal inputs (highest and second priority)
◆ One analog stereo analog audio signal input (3rd priority)
◆ One MPX stereo composite signal input (4th priority)
◆ One I2S digital audio signal input (lowest priority)
• Supports one RDS or SCA subcarrier input
• Support stereo pilot signal and stereo composite signal 19KHz/MPX output
• Upgradeable to FM Synchronous broadcast transmitter
• Electronically controlled AGC controls output power zero drift
• Perfect over-current, over-voltage, over-temperature, over-power, standing wave ratio alarm and protection
• One-touch shuttle quick keyboard input
• Real-time display of operating parameters using OLED
• With TCP/IP, RS232, RS485, CAN communication interface and SMS modem interface
• 19-inch standard chassis, height 2U
The Transmitter Block Diagram:
3. Technical specifications
1. Nominal emission frequency 87MHz～108MHz
(other frequencies can be customized), stepping 10kHz
2. Carrier frequency tolerance ±200Hz
3. Output power 0～30W/0～100W/0～300W
4. Output power stability <±3% (ambient temperature -10 ℃ ~ + 50 ℃)
5. Output impedance 50Ω
6. RF output connector N-50K
7. Residual wave radiation <-80dB
8. Parasitic amplitude modulation noise <-55dB
9. Analog audio input impedance 600Ω balance
10. Analog audio input level -12dBm ~ +8dBm
11. AES input impedance 110Ω balance
12. AES input level -60dBFS～0dBFS
13. MPX input impedance 10kΩ unbalanced BNC
14. MPX input level -15dBm～+15dBm
15. Input audio Level Gain -15dB~+15dB Step 0.1dB
16. RDS / SCA input Unbalanced BNC
17. Audio pre-emphasis 0μs/25μs/ 50μs/75μs optional
18. Signal-to-noise ratio ≥92dB (1kHz, 100% modulation)
19. Distortion <0.01% (30Hz ~ 15000Hz, 100% modulation)
20. Frequency response ±0.01dB (no emphasis, no de-emphasis)
±0.05dB (emphasis, de-emphasis)
21. Stereo separation ≥73dB (30Hz～15000Hz)
22. Left and right channel level difference <0.01dB (100% modulation)
23. 19KHz / MPX output impedance 600Ω, unbalanced BNC
24. 19KHz / MPX output level -15dBm ～ + 15dBm
25. Heat dissipation method Forced convection
26. Power supply voltage 90VAC~265VAC/ 47Hz~63Hz
27. Chassis standard 19" inch
Size 2U (width 484mm × height 88mm × depth 500mm)
28. Total weight 15Kg
29. Operating environment temperature -10 ° C ~ +50 ° C
30. Relative humidity <95%
