Title :
A 0.7-3 GHz GaAs QPSK/QAM direct modulator
Author :
Boveda, A. ; Ortigoso, F. ; Alonso, J.I.
Author_Institution :
Alcatel Standard Electrica, Madrid, Spain
Abstract :
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.<>
Keywords :
III-V semiconductors; MMIC; amplitude modulation; field effect integrated circuits; gallium arsenide; modulators; phase shift keying; 0.7 to 3 GHz; 16 QAM; GaAs; QPSK; SSB; UHF; carrier suppression; differential amplifiers; differential output stage; direct modulator; double balanced FET mixers; phase-shifter; quadrature amplitude modulation; sideband suppression; single sideband; vector modulator; Amplitude modulation; Circuits; Differential amplifiers; Error correction; FETs; Gallium arsenide; Phase modulation; Quadrature amplitude modulation; Quadrature phase shift keying; Radio frequency;
Conference_Titel :
Solid-State Circuits Conference, 1993. Digest of Technical Papers. 40th ISSCC., 1993 IEEE International
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-0987-1
DOI :
10.1109/ISSCC.1993.280022
