Patent
Hybrid polar/cartesian digital modulator
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TLDR
In this article, a hybrid Cartesian/polar digital QAM modulator was proposed, which utilizes a combination of an all digital phase locked loop (ADPLL) that features a wideband frequency modulation capability and a digitally controlled power amplifier that features interpolation between 90 degree spaced quadrature phases.Abstract:
A novel apparatus and method for a hybrid Cartesian/polar digital QAM modulator. The hybrid technique of the present invention utilizes a combination of an all digital phase locked loop (ADPLL) that features a wideband frequency modulation capability and a digitally controlled power amplifier (DPA) that features interpolation between 90 degree spaced quadrature phases. This structure is capable of performing either a polar operation or a Cartesian operation and can dynamically switch between them depending on the instantaneous value of a metric measured by a thresholder/router. In this manner, the disadvantages of each modulation technique are avoided while the benefits of each are exploited.read more
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References
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Proceedings ArticleDOI
A 3V CMOS 400mW 14b 1.4GS/s DAC for multi-carrier applications
B. Schafferer,Robert Adams +1 more
TL;DR: In this paper, an uncalibrated 0.18 /spl mu/m CMOS 14 bit 1.4 GS/s DAC with an LVDS interface was presented, which achieves 67 dB SFDR for a 260 MHz full-scale tone and 70 dB ACLR for a two-carrier output, centered at 470 MHz.
Journal ArticleDOI
Radio frequency digital-to-analog converter
TL;DR: In this article, a DAC output controlled by an oscillating waveform is proposed to mitigate the effects of switching distortion and clock jitter in high-frequency digital-to-analog converters.
Patent
Hybrid polar modulator differential phase cartesian feedback correction circuit for power amplifier linearization
TL;DR: In this article, a method for estimating the phase and amplitude distortions introduced by radio frequency or microwave power amplifiers even where polar modulation is used is presented. But this method is not suitable for the case of large amplitude amplifiers.
Journal ArticleDOI
A digital quadrature modulator with on-chip D/A converter
TL;DR: A digital quadrature modulator is presented that can replace the first analog IF mixer stage of a base station transmitter and is designed to fulfil the spectral, phase, and EVM specifications of GSM, EDGE and WCDMA base stations.
Journal ArticleDOI
Improved digital-IF transmitter architecture for highly integrated W-CDMA mobile terminals
TL;DR: An improved digital intermediate frequency (IF) transmitter architecture for wide-band code-division multiple-access (W-CDMA) mobile terminals is proposed, taking full advantage of complimentary metal-oxide-semiconductor technology scaling by employing digital processing to ease analog complexities.