Can a FPGA be used as a GMSK demodulator?
Along with this thesis, GMSK modulation/demodulation has implemented on FPGA with VHDL to use in a SDR project which is planned to be placed in a cube satellite. The motivation for this project is, providing a flexible system that even baseband carrier frequency can be changed by reprogramming FPGA.
How to get IQ data from rtl-sdr dongle?
To get from the unsigned (0 to 255) range we need to subtract 127.5 from each I and Q value, which results in a new range from -127.5 to +127.5. Then the complex data is simply y = I + jQ. We perform this using Matlab by applying the following custom function loadFile, which is presented below.
What is the sample rate for gqrx SDR?
The GQRX SDR applications runs. I set the sample rate to be 2500000 samples/second, which equates to a 2.5 MHz bandwidth, and I set the center frequency to 100.122 MHz. Below is a screenshot of the GQRX application.
How are SDR signals converted to analog signals?
A SDR processes digitally converted signals and data compared to analog signals in analogue radio. The data is digitized via an Analog to Digital Converter (ADC). The ideal receiver scheme contains an ADC to an antenna.
How is GMSK used in many cube satellites?
Many cube satellite has mostly 2 different modulation option for communication. Frequency shift keying (FSK) and Gaussian minimum shift keying (GMSK). Our motivation for this projec t is to provide a flexible sy stem for c ube satellites. There architecture.
Can a GMSK modulator be used on a satellite computer?
Finally, the GMSK modulator/demodulator is merged with the old system and tested with a satellite computer model. As a satellite computer an MSP430 family device is used. The merged system has the options serial peripheral interface (SPI), (I2C) to communicate with other devices and satellite computer.