A Multi-Level Pulse Modulated Polar Transmitter Using Digital Pulse-Width Modulation

Chen, Jau-Horng; Yang, Hao-Shun; Chen, Yi-Jan Emery

doi:10.1109/lmwc.2010.2045599

Cited by 34 publications

(20 citation statements)

References 5 publications

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“…Sequence 1, which we will refer to as a Vertical Fill Sequence (VFS), fills slots vertically as the amplitude is increased. This sequence is similar to previously proposed designs [25]. In contrast, Sequence 2, which we will refer to as a Horizontal Fill Sequence (HFS), fills the slots horizontally as the amplitude is increased, i.e., slots in the same amplitude level are filled before slots in the next higher amplitude level.…”

Section: A Hybrid Amplitude/time Encodingmentioning

confidence: 69%

“…The proposed hybrid encoding scheme encompasses previously proposed multi-level PWM schemes as special cases [23], [25]. As we will discuss, hybrid amplitude/time encoding represents a large design space of alternatives, both in terms of constructing the multi-level signal and its decomposition into binary-level PWM signals that feed the SMPAs.…”

Section: Proposed Hybrid Amplitude/time Encoding Techniquementioning

confidence: 99%

“…The in-band power is (21) where is one minimal output step given by (22) We notice that is only a function of the number filled slots and does not depend on the fill sequence. The total power, , is given by (23) Minimizing is equivalent to (24) The condition is satisfied by minimizing the occurrences of (25) Equation (25) indicates that minimal total power (equivalently the highest coding efficiency) is reached by avoiding filling slots at the same th column in the design space.…”

Section: Appendixmentioning

confidence: 99%

See 2 more Smart Citations

A Hybrid Amplitude/Time Encoding Scheme for Enhancing Coding Efficiency and Dynamic Range in Digitally Modulated Power Amplifiers

Xia

Garg

Boumaiza

2013

IEEE J. Emerg. Sel. Topics Circuits Syst.

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Digitally modulated power amplifiers (DMPA) are a promising architecture for practical and highly efficient softwaredefined radio transmitters. Signal encoding schemes for DMPAs have primarily focused either on amplitude or time domain encoding, neither of which can simultaneously provide high coding efficiency, high dynamic range and low design complexity. In this paper, we propose, analyze and evaluate a new hybrid amplitude/ time signal encoding scheme that significantly improves the coding efficiency and dynamic range of DMPAs without significantly increasing design complexity. The proposed hybrid amplitude/time encoding scheme combines both the amplitude domain and the time domain to optimally encode information. Evaluation results show that hybrid amplitude/time encoding yields a 35% increase in the average coding efficiency with respect to conventional time encoding, and is only 6.7% lower than peak efficiency when applied to a Wireless Local Area Network signal with a peak to average power ratio equal to 9.9 dB. A new DMPA architecture, based on the proposed hybrid encoding, is also proposed.Index Terms-Digital encoder, digitally modulated power amplifier, pulse-width modulation, software-defined ratio.

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Section: A Hybrid Amplitude/time Encodingmentioning

confidence: 69%

Section: Proposed Hybrid Amplitude/time Encoding Techniquementioning

confidence: 99%

Section: Appendixmentioning

confidence: 99%

See 1 more Smart Citation

A Hybrid Amplitude/Time Encoding Scheme for Enhancing Coding Efficiency and Dynamic Range in Digitally Modulated Power Amplifiers

Xia

Garg

Boumaiza

2013

IEEE J. Emerg. Sel. Topics Circuits Syst.

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“…This RF-CAB architecture is a good system-level idea, which along with its theoretically promised performance, turned it into a topic of active research, as in [2][3][4][5][6][7][8][9][10], where the system was partially addressed in its individual blocks. However, the reconstruction BPF was neither included in simulations nor measurements.…”

Section: Introductionmentioning

confidence: 99%

Radio frequency carrier amplitude‐burst transmitters – from architecture to circuit

Pires

Cabral

Pedro

2015

IET Microwaves, Antennas & Propagation

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The radio frequency carrier amplitude-burst transmitter constitutes a promising architecture capable of efficiently transmitting signals of highly demanding complex modulation schemes. However, the tested practical implementations present results that stay way behind the theoretically advanced promises. This study presents the first thorough study of the power efficiency and linearity characteristics that can be actually achieved with this architecture. The analysis starts with a brief revision of the theoretical idealised behaviour of these switched-mode amplifier systems, followed by the study of the many sources of impairments that appear in their real implementation. In particular, a special attention is paid to the dynamic load modulation caused by the often ignored interaction between the narrow-band signal reconstruction filter and the switched-mode power amplifier. The performance of this architecture is clearly explained based on the presented theory, which is supported by simulations and corresponding measurement results of a fully working implementation. The drawn conclusions allowed the development of a set of design rules for future improvements.

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“…The multi-level PWM transmitter (ML-PWMT) [68,69,78,79] uses multiple PWM signals in order to improve the amplitude resolution, which results in an improved dynamic range. However, the major issue for the transmitter is the larger chip area, which is due to the requirement of multiple PAs followed by a power combiner.…”

Section: Conceptmentioning

confidence: 99%

Pulse-Width Modulated RF Transmitters

Haque¹

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To my mother, father, and uncle (mamoo), AbstractThe market for wireless portable devices has grown significantly over the recent years. Wireless devices with ever-increased functionality require high rate data transmission and reduced costs. High data rate is achieved through communication standards such as LTE and WLAN, which generate signals with high peak-to-average-power ratio (PAPR), hence requiring a power amplifier (PA) that can handle a large dynamic range signal. To keep the costs low, modern CMOS processes allow the integration of the digital, analog and radio functions on to a single chip. However, the design of PAs with large dynamic range and high efficiency is challenging due to the low voltage headroom.To prolong the battery life, the PAs have to be power-efficient as they consume a sizable percentage of the total power. For LTE and WLAN, traditional transmitters operate the PA at back-off power, below their peak efficiency, whereas pulse-width modulation (PWM) transmitters use the PA at their peak power, resulting in a higher efficiency. PWM transmitters can use both linear and SMPAs where the latter are more power efficient and easy to implement in nanometer CMOS. The PWM transmitters have a higher efficiency but suffer from image and aliasing distortion, resulting in a lower dynamic range, amplitude and phase resolution.This thesis studies several new transmitter architectures to improve the dynamic range, amplitude and phase resolution of PWM transmitters with relaxed filtering requirements. The architectures are suited for fully integrated CMOS solutions, in particular for portable applications.The first transmitter (MAF-PWMT) eliminates aliasing and image distortions while allowing the use of SMPAs by combining RF-PWM and band-limited PWM. The transmitter can be implemented using all-digital techniques and exhibits an improved linearity and spectral performance. The approach is validated using a Class-D PA based transmitter where an improvement of 10.2 dB in the dynamic range compared to a PWM transmitter for a 1.4 MHz of LTE signal is achieved.The second transmitter (AC-PWMT) compensates for aliasing distortion by combining PWM and outphasing. It can be used with switch-mode PAs (SMPAs) or linear PAs at peak power. The proposed transmitter shows better linearity, improved spectral performance and increased dynamic range as it does not suffer from AM-AM distortion of the PAs and aliasing distortion due to digital PWM. The idea is validated using push-pull PAs and the proposed transmitter shows an improvement of 9 dB in the dynamic range as compared v vi Abstract to a PWM transmitter using digital pulse-width modulation for a 1.4 MHz LTE signal.The third transmitter (MD-PWMT) is an all-digital implementation of the second transmitter. The PWM is implemented using a Field Programmable Gate Array (FPGA) core, and outphasing is implemented as pulse-position modulation using FPGA transceivers, which drive two class-D PAs. The digital implementation offers the flexibility to adapt the transmitter...

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A Multi-Level Pulse Modulated Polar Transmitter Using Digital Pulse-Width Modulation

Cited by 34 publications

References 5 publications

A Hybrid Amplitude/Time Encoding Scheme for Enhancing Coding Efficiency and Dynamic Range in Digitally Modulated Power Amplifiers

A Hybrid Amplitude/Time Encoding Scheme for Enhancing Coding Efficiency and Dynamic Range in Digitally Modulated Power Amplifiers

Radio frequency carrier amplitude‐burst transmitters – from architecture to circuit

Pulse-Width Modulated RF Transmitters

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