... for
- multiband GNSS (or other L-band signal) acquisition and processing if a power combiner (e.g. MiniCircuits ZAPD-2DC+) is used to feed both chips with the signal coming from a single multiband antenna
- CRPA (Controlled Radiation Pattern Antenna) if each chip is fed from a different antenna for spatial diversity
- applicable to any L-band communication systems sampled with 2-3 bit ADC (verified with Iridium)
Assembled daughter board: the missing 24 MHz oscillator is replaced with the 24 MHz output from one of the resonator pins fitted on the FX2LP board. However, the frequency pulling by the capacitor leads to a 3 kHz offset (2 ppm) which must be compensated for when processing (acquisition phase of GNSS signal analysis) the recorded signals.
Processing relies on the PocketSDR software provided by Tomoji Takasu at https://github.com/tomojitakasu/PocketSDR.
The firmware for the FX2LP is compiled using opensource tools including the
sdcc compiler, fx2lib library, cycfx2prog for prototyping the 8051 embedded
software and fxload for flashing the onboard EEPROM.