Congreso internacional:
Año: 1993, A 0,7-3GHz GaAs QPSK/QAM Direct Modulator
Congreso: 1993 IEEE International Solid-State Circuits Conference Digest of Technical Papers. San Francisco, CA. USA. 24-26 febrero 1993.
Autores: Angel Bóveda, Félix Ortigoso and José I. Alonso
A vector modulator which contains a 90 degrees phase-shifter, two pairs of differential amplifiers, two double balanced FET mixers, and a differential output stage within a single chip is described. The QPSK and 16 QAM (quadrature amplitude modulation) constellations are measured with a vector network analyzer. The output spectrum of the SSB (single sideband) modulation is shown, demonstrating that the carrier suppression and the sideband suppression are better than 40 dBc. Third-order intermodulation tones are less than -40 dBc, while carrier suppression is better than 40 dBc.
