Distortionless RF pulse width modulation

Wagh, P.; Midya, P.; Rakers, P.

doi:10.1109/mwscas.2002.1187172

Cited by 4 publications

(2 citation statements)

References 6 publications

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“…Therefore, all other signal information has to be encoded in the timing of the signal, which still can apply very high resolution as the amplifier is a time-continuous system. Many time-continuous modulators such as PWM [4], Click [5], or Neoteric [6] exploit the accuracy that can be accomplished by fully utilizing the non-discrete nature of the timing information; but they suffer from implementational problems related to their analog nature, like the need for tightly tolerated components, high-power consumption, and considerable chip size requirements. On the digital side, the two common implementations are envelope DSM (EDSM [7, 8]) and BPDSM.…”

Section: Coding Schemementioning

confidence: 99%

A new modulator for digital RF power amplifiers utilizing a wavetable approach

Huhn

Wentzel

Heinrich

2017

Int. J. Microw. Wireless Technol.

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This paper presents for the first time a wavetable-based coding scheme to generate a high-speed binary input signal for digital RF power amplifiers. The approach maximizes the utilization of the time domain handling capabilities of the pulse forming circuit. Key features are a greatly improved output spectrum purity in comparison with common digital modulators, the ability to adjust the modulator to any given pulse forming hardware and a built-in signal correction option that comes without additional computational cost. To give a first impression on the modulators behavior and its possibilities to adapt to different hardware constraints, simulations are carried out for different parameter variations and for different baseband bandwidths. Furthermore, the proposed concept is emulated with an arbitrary waveform generator to gather additional measurement data. For a 5 MHz wideband code division multiple access (WCDMA) signal (6.5 dB peak-to-average power ratio) at 900 MHz, an error vector magnitude (EVM) of 0.26% and better than >58 dB adjacent channel leakage ratio (ACLR) were recorded. To the authors’ knowledge, these are the best values achieved so far for a single-bit coding scheme without digital predistortion that still maintains maximum power coding efficiency.

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Section: Coding Schemementioning

confidence: 99%

A new modulator for digital RF power amplifiers utilizing a wavetable approach

Huhn

Wentzel

Heinrich

2017

Int. J. Microw. Wireless Technol.

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“…Considering the fact that switching amplifiers always perform at peak efficiency because they always operate at full signal swing, one should encode the amplitude information into the time domain such that the amplitude of the input signal is always maximal. In literature, there are two main trends in encoding the envelope of the signal into time domain: burst mode modulation [4, 5] and RF pulse width modulation (PWM) [4, 6–9]. The latter is translating the varying amplitude information into a varying pulse width.…”

Section: Introductionmentioning

confidence: 99%

Efficiency and linearity analysis of a burst mode RF PA with direct filter connection

Francois

Singerl

Wiesbauer

et al. 2011

Int. J. Microw. Wireless Technol.

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Burst mode operation is proposed as an efficiency improving technique for power amplifiers. The core idea is to modulate the amplitude of the envelope signal into a series of square-wave pulses such that the width of the signal burst or the total amount of pulses are varied according to the envelope. The phase information is still contained by the timing of the pulses. This work presents the efficiency and linearity analysis of burst mode radio frequency (RF)/power amplifier (PA). In addition, the efficiency performance is compared when the burst mode RF power amplifiers (PA) is connected to a wideband load or a narrowband filter. It is shown that burst mode PAs are more efficient than the conventional Class B PAs. To achieve an even more favorable efficiency, a transmission line is inserted between the output of the switching RF PA and the filter to improve the filter's impedance characteristic. Additionally, the efficiency and linearity of the burst mode PA with and without transmission line has been studied and simulated thoroughly. To demonstrate the validity of the efficiency formulas and linearity considerations, a printed circuit board (PCB)-mounted burst mode PA using a laterally diffused metal oxide semiconductor (LDMOS) transistor was fabricated. Measurements show a peak efficiency of 78% and 28.8 dBm of output power.

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