A highly integrated single-chip inphase and quadrature (I/Q) modulator is implemented for low power mobile applications (AMPS, ADC, GSM). A quadrature carrier is generated internally without having an external phase shift network. Baseband signals can modulate these carriers directly in the 900 MHz range. A variable gain amplifier with good linearity performance is incorporated to meet tough digital cellular requirements for linear modulation. The device contains an on-chip frequency divider, a crystal osciillator, phase detector, and VCO, which combine to form a PLL for analog FM modsulation (pure AMPS system) and frequency synthesizing. It also has three additional dividers for generating clock signal for a micro-controller, DSP chip, and system timing unit. All the functions of the device are controlled by a three-wire data bus, which can be connected to the system micro-controller in the receiver. The I/Q modulator can achieve 40 dBc carrier and sideband suppression when single sideband modulation is applied.
Implementation of a 900 MHz transmitter system using highly integrated ASIC
Einführung eines Übertragungssystems bei 900 MHz mit hochintegrierten Kundenschaltungen
VTC, IEEE Vehicular Technology Conference, 44 ; 2 ; 1341-1345
1994
5 Seiten, 7 Bilder, 7 Quellen
Aufsatz (Konferenz)
Englisch
spannungsgesteuerter Oszillator , VLSI-Schaltung , Quadraturmodulation , PLL (Phasenregelkreis) , Phasenverschiebung , Frequenzmodulation , Transistorverstärker , Proportionalität , Übertragungsfunktion , Frequenzteilung , Phasenmessung , Quarzoszillator , Frequenzsynthese , Taktgeber , Zeitgeber , Regelkreis , Mikroprozessor , Datenbus , Sende-Empfangs-Gerät , Nebenzipfeldämpfung , L-Band , Verlustleistung , Linearverstärker , Blockschaltbild , Kundenschaltung
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