Effect of modulation scheme on LINC transmitter power efficiency

Sundstrom, L.; Johansson, Mikael

doi:10.1049/el:19941116

Cited by 32 publications

(15 citation statements)

References 4 publications

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“…1 produce PDFs that are concentrated primarily in the upper half of the voltage range and have peak-to-average ratios on the order of 3-6 dB [1]. Noise and multiple carriers amplified simultaneously have a Rayleigh-distributed envelope [2] with a peak-to-average ratio (typically) from 6 to 13 dB.…”

Section: Average Efficiencymentioning

confidence: 99%

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L-band transmitter using Kahn EER technique

Raab

Sigmon

Myers

et al. 1998

IEEE Trans. Microwave Theory Techn.

147

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This paper describes a 20-W peak-envelope power linear L-band transmitter based upon the Kahn envelope-elimination-and-restoration technique. A double envelope-feedback loop assures high linearity. The radiofrequency (RF) power amplifier employs a two-stage monolithic-microwave integrated-circuit driver amplifier and a 20-W power amplifier biased for class-AB operation. The class-S modulator includes a high-speed comparator and 1/2-m heterojunction field-effect transistors in its output stage. A double envelope-feedback loop assures both high linearity and time-delay equalization for RF bandwidths to 150 kHz. With a two-tone signal, the transmitter achieves an efficiency of 56% at full power (41 dBm), and 35% at 18 dB into back-off. The third-order intermodulation distortions for a two-tone signal vary from 030 to 040 dBc over a 20-dB range of back-off. For quaternary phase-shift keying, the first and second adjacent-channel powers are 048 and 057 dBc.

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Section: Average Efficiencymentioning

confidence: 99%

“…It is obtained [3] by averaging the output and input powers and then computing (1) The average efficiency of an ideal class-B PA is 59% and 28% for the OQPSK PDF (square-root raised-cosine (SRRC),…”

Section: Average Efficiencymentioning

confidence: 99%

L-band transmitter using Kahn EER technique

Raab

Sigmon

Myers

et al. 1998

IEEE Trans. Microwave Theory Techn.

147

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“…One is the hybrid, such as Wilkson combiner, which is matched and lossy. The outphasing portion power of two PA outputs is consumed at the resistor of the combiner, so the efficiency of this class is low [3]. The other one is the unmatched but lossless, such as Chireix combiner.…”

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confidence: 99%

A new impedance match method to improve efficiency of LINC with Chireix combiner

Liu

2010

Micro & Optical Tech Letters

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In this article, we propose a new impedance match method in serial Chireix combiner to improve the efficiency of Linear amplification with Nonlinear Components (LINC) amplifier. Based on the impedance characteristics of the serial Chireix combiner, two transmission lines are added between power amplifiers (PAs) and Chireix combiner in LINC. For experimental verification, the PAs and combiner are implemented and tested. From the measured results, this method is proved available for improving efficiency of LINC, and convenient for design as well as tuning work. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1418–1421, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25205

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“…Thus, when the two phasors are substantially out of phase most of the power generated by the PAS is within the e ( t ) and -e ( t ) components and, hence, wasted as heat without contributing anything to the final output. The average power efficiency is therefore reduced significantly, especially for higher order modulations that have significant envelope variations and spend most of time at low envelope levels [3].…”

Section: S L ( T ) = S I ( T ) + E ( T ) S 2 ( T ) = S I ( T ) -E ( T )mentioning

confidence: 99%

“…The realization of this high level of power efficiency, however, is critically dependent on the output combiner. If a conventional power combiner (hybrid combiner) is used, the average power efficiency will be reduced significantly due to the power wasted in the load when the two amplifiers are operated substantially out of phase [3]. To overcome this problem, one way is to reuse that otherwise wasted energy.…”

Section: Introductionmentioning

confidence: 99%

Investigation of a highly efficient LINC amplifier topology

Shi

Sundstrom²

IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211)

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The LINC transmitter is an architecture that provides linear amplification using nonlinear but power efficient amplifiers. The realization of the high power efficiency potential is the most critical issue of LINC. We have investigated a promising LINC amplifier topology that using ideal bilateral PA devices theoretically achieves linear amplification with 100% efficiency at all output levels. Circuit simulations based on integrated circuit (IC) techniques show good linearity and power efficiency results up to a few hundred MHz but gradually degrading performance as we approach the GHz range. With the advance of IC technology, this LINC amplifier topology does offer a good possibility for obtaining highly efficient linear RF power amplifiers.

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Effect of modulation scheme on LINC transmitter power efficiency

Cited by 32 publications

References 4 publications

L-band transmitter using Kahn EER technique

L-band transmitter using Kahn EER technique

A new impedance match method to improve efficiency of LINC with Chireix combiner

Investigation of a highly efficient LINC amplifier topology

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