Simulated tolerance of loop parameters of Cartesian feedback amplifier for pi /4-shifted QPSK transmitter

Evaluates Cartesian feedback amplifier performance for a mobile terminal for a digital cellular system using pi /4-shifted QPSK. To determine the out-of-band emission, the authors calculated spectra in peak-hold mode based on RCR Standard STD-27 on Japan Digital Cellular Telecommunication System. They calculated the tolerance of the feedback amplifier's loop parameters, assuming TDMA system parameters based on the RCR specifications. Since the specifications for out-of-band emission of -45 dB at 50 kHz and -60 dB at 100 kHz from the band center were satisfied, the Cartesian feedback amplifier is applicable to a TDMA transmitter and is easily implemented for practical applications.<
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