GaAs MESFET Regenerator for Phase-Shift Keying Signals at the Carrier Frequency

Direct Phase Regeneration of a 400 Mbit/s QPSK Signal at 1.7 GHz

“…For example, a 2R repeater, using a direct phase 'regenerator can discriminate and reshape without use of a detector and a modulator [3]. Hence, the cost of a hybrid system can be reduced, as compared with the 3R repeater system.…”

“…This bi-phase regenerator is feasible using an FET mixer [3], whose local oscillator frequency is just twice that of the input carrier. The converted signal has an inverse phase, -4, compared to the input signal i.e., cos ( 2 0 t -(ut + 4)) = cos (ut -4).…”

“…2, This DPR has two BPSK-DPR's, which consist of a bi-phase regenerator and a limiter [3]. The bi-phase regenerator regenerates the input signal phase to 0 -n states, when the input signal amplitude is equal to the converter signal amplitude.…”

New direct regenerator for 16-ary QAM signalling

“…The principle of operation is described in the following Section. Direct regeneration of digitally modulated carriers has received considerable attention from many researchers in recent years [5][6][7][8][9][10]. The first GaAs MESFET binary PSK direct phase regenerator was proposed by Komaki et al [5].…”

“…* A QRC can be realised with a simple GaAs MESFET mixer and a bandpass filler [5] We may proceed, now, to determine the signal S out {t) at the output of the 16-ary QAM regenerator. Consider, first, the upper section of the regenerator, namely, QRC followed by bandpass limiter.…”