A 120-Mbit/s TDMA QPSK modem for on-board applications
Abstract
A C-band 120-Mbit/s QPSK modem is designed to operate in either continuous or burst mode within the Intelsat frame-defined TDMA format. A demodulation/remodulation approach is used for phase-coherent recovery. The demodulator detects orthogonal data streams at baseband directly from the 4-GHz QPSK signal. The modulated bit-energy to noise-power-density ratio is found to be within 1.2 dB of that of an ideal demodulator at a bit error rate of 10 to the -6th. The demodulator has low (3.3 W) total power consumption, and it is realized in three microwave integrated circuit modules: (1) an RF remodulation module; (2) an emitter-coupled logic regeneration module; and (3) a phase-locked loop.
- Publication:
-
COMSAT Technical Review
- Pub Date:
- 1987
- Bibcode:
- 1987COMTR..17...23E
- Keywords:
-
- Communication Satellites;
- Modems;
- Onboard Data Processing;
- Phase Shift Keying;
- Satellite Transmission;
- Time Division Multiple Access;
- Transponders;
- Bit Error Rate;
- Demodulators;
- Equivalent Circuits;
- Frequency Response;
- Integrated Circuits;
- Superhigh Frequencies;
- Synchronism;
- Electronics and Electrical Engineering