Title :
Miniaturized reverse modulation loop for a CQPSK 120-Mbit/s modem
Author :
Ralston, K.K. ; Gupta, R.K. ; Assal, F.T. ; Kroll, R.T.
Author_Institution :
COMSAT Lab., Clarksburg, MD, USA
Abstract :
The design and performance of a miniaturized reserve modulation loop (RML) for carrier recovery in a 120-Mb/s coherent quadrature phase shift keying (CQPSK) modem for onboard satellite applications are discussed. The RML circuit, consisting of modulator, demodulator, and comparator circuits, has been fabricated using quasi-monolithic techniques with dimensions of 1.65*4 cm. The relative phase for all four states of the modulator is in close agreement with design values of 90 degrees +or-1 degrees over a 200-MHz bandwidth at 3.95 GHz. The demodulator and comparator circuits of the RML have successfully recovered a 120-Mb/s bit stream.<>
Keywords :
MMIC; digital communication systems; modems; phase shift keying; satellite relay systems; 120 Mbit/s; 200 MHz; 3.95 GHz; CQPSK; MMIC fabrication techniques; carrier recovery; coherent quadrature PSK; comparator circuits; demodulator; miniaturized reserve modulation loop; modem; modulator; onboard satellite applications; phase shift keying; Artificial satellites; Baseband; Bit error rate; Circuits; Delay effects; Demodulation; Hardware; Modems; Phase modulation; Radio frequency;
Conference_Titel :
Microwave Symposium Digest, 1991., IEEE MTT-S International
Conference_Location :
Boston, MA, USA
Print_ISBN :
0-87942-591-1
DOI :
10.1109/MWSYM.1991.147259
