The efficient algorithm and high-performance FPGA are combined to build the FDM Demultiplexer with 24 channel AM-SSB demodulator. The system is very compact with only three modules, an NI-Embedded controller, FlexRIO and an adapter module. The data is acquired and A/D converted at high sampling rate of 100MS/s, which is five times the frequency tuning range (up to 20MHz). The signal is down converted using four efficient IQ DDCs (Digital Down Converters) implemented on FPGA.
These stages are combined to achieve high resolution, accuracy and superior noise performance. The flexibility of the GUI allows choosing between the ITU-T CCITT-2700 and CCITT-960 plans. Apart from this the system is programmed to scan the entire frequency range to detect FDM activity. The demodulated data can be saved to files on disk and given as audio output as well.
Features:
- Frequency tuning range 0 Hz – 20 MHz
- 24 Channel demodulation
- Independent detection and demodulation of up to 2 Groups
- Programmed CCITT 2700, CCITT 960 Frequency plans & Direct Scan Modes
- Output generation in .wav file format
- Selectable first & second groups
- Compact size with a Controller and a Flex RIO Module
- Design implementation on Virtex-5 FPGA
- PXIe platform
- Familiar Windows7 operating system with Easy-to-use GUI
- Remote Operation through Ethernet
Super Master Group, Master Group, Super Group and Group can be specified in CCITT 2700 and CCITT 960 modes to tune to desired groups. The Direct Scan Mode has the scanning capability which allows specifying the Start & Stop Frequencies along with Threshold power level. The demodulators of the system are independent and are tunable to 2 groups (24 channels).