RF Class-D Amplification With Bandpass Sigma&amp;amp;ndash;Delta Modulator Drive Signals

Johnson, Thomas; Stapleton, S.P.

doi:10.1109/tcsi.2006.885980

Cited by 107 publications

(44 citation statements)

References 18 publications

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“…One of the candidates for these features is the class-S family [1,2,3,4] that utilize digital modulation to use a PA in the saturation region. One group of the class-S family uses a delta-sigma modulator (DSM) for an envelope component and is called the envelope delta-sigma modulator (EDSM) transmitter [2,3,4], where an EDSM means the whole structure including a DSM for an envelope component, an up-convertor for a phase component, and a device to recombine the two components.…”

Section: Introductionmentioning

confidence: 99%

Compensation technique for time alignment of envelope and phase paths in an envelope delta-sigma modulator

Lee

Cho

Jung

2015

IEICE Electron. Express

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A compensation technique for time alignment of envelope and phase paths in an envelope delta-sigma modulator (EDSM) is proposed. In this technique, two controllable delays are intentionally added, and a combination of the two delays compensates a time misalignment caused by the inherent processing delay of a delta-sigma modulator (DSM) and the difference of propagation delays on the asymmetric envelope and phase paths. One of the two delays is a digital sample delay, which is added in the digital domain before a digital-to-analog converter (DAC). The other delay is obtained by the use of D flip flops (DFFs) followed by a DSM, which is possible because the output of a DSM is changed by a clock. The validity of the proposed technique is confirmed by simulation.

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Section: Introductionmentioning

confidence: 99%

Compensation technique for time alignment of envelope and phase paths in an envelope delta-sigma modulator

Lee

Cho

Jung

2015

IEICE Electron. Express

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“…A class-S PA consists of three major blocks: a sigma-delta (ΣΔ) modulator that encodes the input RF signal into a pulse stream, a switch-mode PA (SMPA), and a bandpass filter ( Fig. 1) [1], [2]. The encoded pulse stream RF input drives the transistors in SMPA into on and off regions, offering potentially 100% power efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…A common technique utilizes direct bandpass ΣΔ (BP ΣΔ) modulator. The BP ΣΔ modulator's input is fed with a complex signal at a carrier frequency f C with f C (f ΣΔ /4; f ΣΔ /3) [1], [4]. The major implementation challenge for the direct method is in achieving a sampling rate in a reconfigurable modulator three to four times higher than a carrier frequency, e.g., for f C = 1 GHz, the corresponding sampling rate of the ΣΔ modulator is f ΣΔ = 4 GHz.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from the difference in sampling rates of the ΣΔ and, therefore, signal-to-noise ratios (SNRs), both offer very similar coding efficiencies. When their outputs are binary, then, the resulting coding efficiency is low, often less than 10% [1]. The importance of coding efficiency is seen in [4], where it was demonstrated that a three-level SMPA can have better drain efficiency than the equivalent SMPA driven by two-level pulse stream.…”

Section: Introductionmentioning

confidence: 99%

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Improved Coding-Efficiency Two-Level Source Encoder for RF Switch-Mode Power Amplifiers

Podsiadlik

Dooley

Farrell

2012

IEEE Trans. Circuits Syst. II

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Abstract-A ΣΔ-driven RF switch-mode power amplifier is inherently linear only when it has a two-level output. At the same time, a two-level output generates the largest amount of quantization noise. This brief analyzes the effect of nonequal level spacing in a three-level ΣΔ output and provides a method for shaping the corresponding error noise to regions outside the band of interest. Subsequently, the nonlinearity-shaping property is utilized to obtain an improved two-level drive signal based on three-level ΣΔ modulation. The new binary drive signal is proven to have better adjacent channel leakage ratio and higher coding efficiency than a conventional two-level ΣΔ modulator. In the investigated case, measured coding efficiency improves from 8.9% of the conventional two-level modulator to 21% of the modified two-level modulator.Index Terms-Coding efficiency, sigma delta, switch-mode power amplifier (SMPA).

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“…In advanced transmitting methods using different techniques, such as Envelope Elimination and Restoration (EER) or Polar transmitters [2][3][4][5], delta-sigma based transmitters [6][7][8][9][10] and Linear amplification with Nonlinear Components (LINC) [11,12], the envelope-varying signal is converted to a signal with a constant envelope. Consequently, it is possible to use highly efficient saturated linear amplifiers or switching-mode power amplifiers (SMPAs) such as classes D, E or F [13].…”

Section: Introductionmentioning

confidence: 99%

Time-Interleaved Delta-Sigma Modulator for Wideband Digital GHZ Transmitters Design and SDR Applications

Ebrahimi¹,

Helaoui²,

Ghannouchi³

2011

PIER B

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Abstract-This paper presents a development of a wideband deltasigma modulator for fully digital GHz transmitters. The fully digital RF transmitter is developed as a promising solution for software defined radio (SDR) terminals and applications. The fully digital transmitter consists of a delta-sigma modulator, a highspeed multiplexer and a switching-mode power amplifier. The speed limitation of delta-sigma modulator is the main limitation to increase the signal bandwidth in fully digital transmitters. In this paper, the bandwidth of the fully digital transmitter is increased 8 times using parallel processing time-interleaved architecture, while maintaining the same signal quality. This architecture was implemented on FPGA and tested for different standards (WiMAX and LTE) with a signal bandwidth up to 8 MHz. The concept was assessed in terms of SNDR by using a differential logic analyzer at the output of FPGA, and the SNDR was found to be around 60 dB.

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RF Class-D Amplification With Bandpass Sigma&ndash;Delta Modulator Drive Signals

Cited by 107 publications

References 18 publications

Compensation technique for time alignment of envelope and phase paths in an envelope delta-sigma modulator

Compensation technique for time alignment of envelope and phase paths in an envelope delta-sigma modulator

Improved Coding-Efficiency Two-Level Source Encoder for RF Switch-Mode Power Amplifiers

Time-Interleaved Delta-Sigma Modulator for Wideband Digital GHZ Transmitters Design and SDR Applications

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