A New Quadrature PWM Modulator With Tunable Center Frequency for Digital RF Transmitters

Ruotsalainen, Henri; Arthaber, Holger; Magerl, Gottfried

doi:10.1109/tcsii.2012.2222834

Cited by 28 publications

(12 citation statements)

References 11 publications

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“…Because of practical implementation issues even a perfect input clock duty cycle leads to a small error of the bit lengths. This can be compensated by adjusting clock signal's duty cycle: By superimposing a small second harmonic signal of the clock and í20 í18 í16 í14 í12 í10 í8 í6 í4 í2 [4] and iii) Mancester encoded BPΣΔ [1] adjusting its phase while monitoring bit lengths on a sampling oscilloscope, the error can be reduced to zero.…”

Section: Resultsmentioning

confidence: 99%

“…Fig. 5 shows simulation based signal to noise and distortion ratio (SNDR) and CE as a function of input signal power for the QΣΔPWM based proposed modulator, a conventional QΣΔPWM with additional noise shaping [4] and a BPΣΔ modulator with manchester coding [1]. A complex exponential centered at f IF = 50 MHz was used as an input signal.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, the noise shaping is optimal only at a single frequency setting, which is a limitation for multi-channel operation. Recently an improved design for the quadrature type Q I I I I6: I I6: 3 :0 I,) I,) 3XOVHG PWM encoding (QΣΔPWM) was proposed where a complex BP type noise shaping was adopted to allow f c tuning in digital domain [4]. In addition, the digital f c adjustment is not prone to analog component imperfections related to an up-mixing method, for example with GHz range multiplexers given in [2].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the digital f c adjustment is not prone to analog component imperfections related to an up-mixing method, for example with GHz range multiplexers given in [2]. However, every quadrature type modulator suffers from f c dependent conjugate quantization noise folding [4] that restricts the available tuning range. The work presented here aims at removal of the excess quantization noise in a way which, in contrast to the previous method, does not require additional noise shaping.…”

Section: Introductionmentioning

confidence: 99%

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Quantization noise cancelation scheme for digital quadrature RF pulse encoding

Ruotsalainen

Arthaber

Magerl

2013

2013 IEEE MTT-S International Microwave Symposium Digest (MTT)

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Quadrature type pulsed radio frequency (RF) signal encoding combined with class-S switched-mode power amplification (SMPA) constitute a potential solution for high efficiency RF transmitters. However, the digital center frequency adjustment for such encoding methods is limited by quantization noise folding. In this paper, a novel quantization noise cancelation scheme is proposed that in an ideal case suppresses the folding distortion components completely. In addition, a low complexity practical solution easily embedable in an existing modulator architecture is given. According to the measurement results, up to 7 dB improvement in signal-to-noise-and-distortion ratio was achieved over a total center frequency tuning range of 160 MHz using a 20 MHz LTE signal excitation.Index Terms-4G mobile communication, PWM, radio frequency power amplifiers, sigma delta modulation, software radio.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantization noise cancelation scheme for digital quadrature RF pulse encoding

Ruotsalainen

Arthaber

Magerl

2013

2013 IEEE MTT-S International Microwave Symposium Digest (MTT)

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“…The existing intermediate-frequency (IF) pulse-width modulation (PWM) based fully digital transmitters, with quadrature [1,2] or delay-line [3] architectures, are prone to spectrum aliasing between the IF and the CF. Especially under low CF conditions, the bandpass filter (BPF) fails to suppress the IF component and harmonics closer to the CF signal.…”

mentioning

confidence: 99%

Reconfigurable fully digital transmitter with carrier‐frequency pulse‐width modulation

et al. 2013

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A reconfigurable fully digital transmitter with carrier-frequency (CF) pulse-width modulation (PWM) is implemented in 180 nm CMOS for low CF applications. Through delay lines, baseband phases are mapped to position delays of 1/4 period of a carrier clock. With delay lines based CF PWM, pre-corrected baseband envelopes are converted to pulse-widths of the position-modulated carrier clock. Both the pulse-widths and the positions of the modulated carrier clock are amplified and reshaped to the sine-wave carrier with baseband components by the sequent switched-mode power amplifier and a bandpass filter. The circuit-level simulation results verify that the proposed implementation achieves reconfigurable CF and 20 dB spectrum optimisation, when compared with the existing intermediate-frequency PWM based designs.

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Baseband tuning of Cartesian delta–sigma RF upconverters

Sirmayanti¹,

Bassoo²,

King³

et al. 2014

Electron. lett.

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Many digital delta-sigma radio frequency (RF) upconverters exhibit poor performance when the carrier frequency is tuned away from the centre of the band. The offsetting of signals from the nominal carrier frequency position generates unwanted distortion products which are dominated by the image and third harmonics. It is shown that these products can be moved out of the band by the correct choice of intermediate frequency. A novel technique for shifting both the signal and the noise null to the new frequency position is described.

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A New Quadrature PWM Modulator With Tunable Center Frequency for Digital RF Transmitters

Cited by 28 publications

References 11 publications

Quantization noise cancelation scheme for digital quadrature RF pulse encoding

Quantization noise cancelation scheme for digital quadrature RF pulse encoding

Reconfigurable fully digital transmitter with carrier‐frequency pulse‐width modulation

Baseband tuning of Cartesian delta–sigma RF upconverters

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