The application of digital signal processing to transmitter linearisation

Bateman, A.; Wilkinson, R.J.; Marvill, J.D.

doi:10.1109/eurcon.1988.11105

Cited by 19 publications

(7 citation statements)

References 4 publications

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“…Digital implementations of the SCS have been considered to improve the performances achieved by analog implementations. Today's digital signal processors (DSPs) technology makes it possible to implement the SCS using a standard DSP device [3]- [4]. With such approach, all of the signal processing is done at the base band.…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of Digital Signal Components Separator of LINC Transmitters Using FPGA Processors

Tian

Hammi

Boumaiza

et al. 2007

2007 IEEE International Conference on Signal Processing and Communications

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This paper presents a comparative study of the performances of various digital signal components separator topologies for linear amplification using non linear components based transmitters. The topologies studied use different subcomponents to perform the most computationally demanding part of the digital signal components separator that is the calculation of the square root function. Three cases are considered: the square root function is implemented using a commercially available square root mega-function, a custom designed square root function, and a one dimensional look-up table. The measurement results show that all topologies achieve comparable throughput performances. However, the look-up table implementation reduces the computational complexity and improves the achievable accuracy.

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Section: Introductionmentioning

confidence: 99%

Design and Optimization of Digital Signal Components Separator of LINC Transmitters Using FPGA Processors

Tian

Hammi

Boumaiza

et al. 2007

2007 IEEE International Conference on Signal Processing and Communications

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“…A modification of the LINC technique, the Combined Ana logue Locked Loop Universal Modulator (CALLUM) [5], uses feedback from the output to compensate for drifts in the characteristics of the amplifiers. Cartesian coordinate negative feedback linearization [6]- [7] uses synchronously demodulated signals as the feedback infor mation. These signals are subtracted from the baseband input signals to generate loop error signals.…”

Section: Introductionmentioning

confidence: 99%

Adaptive digital linearization of RF power amplifiers

Lohtia

Goud

Englefield

1995

Can. J. Electr. Comput. Eng.

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The performance of an adaptive digital technique for the linearization of RF power amplifiers is investigated. Cubic spline interpolation is used to estimate the amplifier's AM-AM and AM-PM characteristics. Using the computed characteristic coefficients, the baseband input signal is appropriately predistorted to compensate for the amplifier nonlinearity. This method has significantly better suppression of the intermodulation products than other predistortion techniques. The out-of-band power emission is also significantly reduced. The performance of baseband predistortion linearization techniques is adversely affected by modulator and demodulator impairments. A digital correction technique is presented to compensate for these imperfections. In this technique, part of the RF signal is fed to an envelope detector. The detector output and the baseband signal are used to estimate the impairment values, using the Newton-Raphson method. The estimated impairment values are then used to compensate for the modulator/demodulator impairments. Spurious signals can be suppressed by more than 30 dB using this technique. Cet article traite de la performance d'une technique adaptative numlrique pour la linearisation d'amplificateurs de puissance RF. Une interpolation spline cubique est utilised pour estimer les caractlristiques AM-AM et AM-PM de l'ampliflcateur. A partir des coefficients calculus, le signal d'entrle en bande de base est prfctistorsionne' en vue de compenser la non-linlarite' de l'ampliflcateur. Cette m&hode rlsulte en une suppression significativement meilleure des produits d'intermodulation que d'autres techniques de prldistorsion, et la puissance 6mise hors bande estIgalement rlduite de maniere significative. La performance des techniques de linearisation par prldistorsion en bande de base est affectle par les imperfections du modulateur et du dlmodulateur, et une technique de correction numlrique est prlsentle pour leur compensation, dans laquelle une partie du signal RF est envoyle a un dltecteur d'enveloppe. La sortie du dltecteur et le signal en bande de base sont utilises pour estimer la valeur des imperfections avec la mlthode Newton-Raphson, et pour compenser les imperfections du modulateur/dlmodulateur. Le niveau des signaux non-dlsires peut £tre r£duit de plus de 30 dB.

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“…Then, this I/Q pairs of signals are up-converted to RF by two mixers. The SCS can be realized with either analog circuits [6][7] or a DSP [8][9][10]. In either case, a significant portion of the circuit is still analog, and any mismatch in phase or amplitude between two paths can potentially ruin the performance of the whole transmitter.…”

Section: Conventional Scs Techniquesmentioning

confidence: 99%

“…2(d), a Combined Analog LockedLoop Universal Modulator (CALLUM) transmitter incorporates the component separation and upconversion simultaneously by employing two VCOs [16]. With appropriate control signals, two VCOs can generate the desired phase-modulated components of a LINC system.…”

Section: Conventional Scs Techniquesmentioning

confidence: 99%

A CMOS Outphasing Transmitter Using Two Wideband Phase Modulators

Lee¹,

Kım²,

Song³

et al. 2011

JSTS:Journal of Semiconductor Technology and Science

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Abstract-This paper describes a CMOS outphasing transmitter using two wideband phase modulators. The proposed architecture can simplify the overall outphasing transmitter architecture using two-point phase modulation in phase-locked loop, which eliminates the necessity digital-to-analog converters, filters, and mixers. This architecture is verified with a WCDMA signal at 1.65 GHz. The prototype is fabricated in standard 130 nm CMOS technology. The measurement results satisfied the spectrum mask and 4.9% EVM performance.

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The application of digital signal processing to transmitter linearisation

Cited by 19 publications

References 4 publications

Design and Optimization of Digital Signal Components Separator of LINC Transmitters Using FPGA Processors

Design and Optimization of Digital Signal Components Separator of LINC Transmitters Using FPGA Processors

Adaptive digital linearization of RF power amplifiers

A CMOS Outphasing Transmitter Using Two Wideband Phase Modulators

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