A Cellular Multiband DTC-Based Digital Polar Transmitter With −153 dBc/Hz Noise in 14-nm FinFET

Palaskas, Y.; Plechinger, P.; Ravi, Ashoke; Degani, Ofir; Banin, Rotem; Gordon, E.; Boos, Z.; Madoglio, Paolo; Angel, J.; Tomasik, Jakob M.; Hampel, S.; Schubert, P.; Preyler, Peter; Mayer, Thomas; Bauernfeind, T.

doi:10.1109/lssc.2019.2933802

Cited by 7 publications

(5 citation statements)

References 6 publications

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“…× E e j ωδ k − j ωδ 0 2π T out e j ωkT out dω. (18) With the definition of the joint characteristic function (CF) of the random variables δ k and δ 0…”

Section: Mathematical Model Of Dithering Dtc-based Frequency Synmentioning

confidence: 99%

“…If the DTC is pre-distorted, e.g. with a look-up table (LUT), it results in a change of the residual INL in the calibrated system which comprises the DTC with its digital pre-distortion [18]. This is a challenge for the additive optimal dither method and would lead to spurious emissions if the calibration is not matching the system.…”

Section: Dither Comparisonmentioning

confidence: 99%

“…The effect of a DTC which is capable of generating an output in the GHz range on generating spurs in the output power spectral density (PSD) is shown in [16]. Circuit implementations of the DTCs discussed there are presented in [17] and [18]. The recent design in [18] operates with a higher frequency digital controlled oscillator (DCO) in the 8 GHz range and generates an output frequency in the range of 0.7 to 2.2 GHz which makes this DTC effectively a fractional divider.…”

mentioning

confidence: 99%

“…Circuit implementations of the DTCs discussed there are presented in [17] and [18]. The recent design in [18] operates with a higher frequency digital controlled oscillator (DCO) in the 8 GHz range and generates an output frequency in the range of 0.7 to 2.2 GHz which makes this DTC effectively a fractional divider. A very similar circuit has been used in recent work directly as a fractional-N frequency divider [19].…”

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confidence: 99%

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Dithering Concepts for Spur-Free Nonlinear DTC-Based Frequency Synthesizers

Preissl

Preyler

Springer

et al. 2021

IEEE Trans. Circuits Syst. I

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Digital-to-time converters (DTCs) are a promising technology for radio frequency (RF) transceivers but are prone to spur generation. A common approach to change the spurious emissions to a spur-free shape is a method called dithering. The power added due to dithering is an important aspect of this approach and gives raise to investigations on additive dither as well as methods for subtractive dithering. This work presents a mathematical model for dithering DTC-based local oscillator (LO) generators. It proposes concepts for the application of subtractive dither and it introduces a novel generalization of quantization-dither to allow for optimal dithering of nonlinear quantizers.

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“…× E e j ωδ k − j ωδ 0 2π T out e j ωkT out dω. (18) With the definition of the joint characteristic function (CF) of the random variables δ k and δ 0…”

Section: Mathematical Model Of Dithering Dtc-based Frequency Synmentioning

confidence: 99%

Section: Dither Comparisonmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Dithering Concepts for Spur-Free Nonlinear DTC-Based Frequency Synthesizers

Preissl

Preyler

Springer

et al. 2021

IEEE Trans. Circuits Syst. I

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“…The phase modulation signal φ [n] is fed into an RF-phase modulator which is generating a phase modulated square-wave carrier where the positions of rising and falling edges in every RF cycle are controlled. The RF-phase modulator is usually realized by a phaselocked loop (PLL) [19] or via the usage of digital-to-time converters (DTCs) [20]- [24]. In the last step the amplitude signal is applied together with the phase modulated squarewave carrier to a radio frequency digital-to-analog converter (RF-DAC) [25], [26] generating the RF output signal at the desired carrier frequency f c .…”

Section: Introductionmentioning

confidence: 99%

Analysis of Spectral Degradation and Error Compensation in 5G NR Digital Polar Transmitters

Preissl

Preyler

Mayer

et al. 2020

IEEE Trans. Circuits Syst. I

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Cellular standards evolve to support increasingly higher bandwidths which results in strict in-and out-of-band requirements such as lower error vector magnitude (EVM) and/or adjacent channel leakage ratio (ACLR). Digital polar transmitters, which are showing the best performance in terms of power consumption, are challenged to fulfill these requirements. This work will show that even in case of ideal analog components and infinite digital resources, there are principle limitations in terms of out-of-band noise for digital polar transmitters. A typical polar modulation will be compared to a theoretical signal with continuous amplitude modulation. The analysis of the resulting error signal suggests a decomposition into two components which can be partially compensated in the amplitude and phase modulation paths. Based on that decomposition a compensation algorithm has been developed and evaluated with a 400 MHz 5G New Radio (NR) signal for Band n257 on Frequency Range 2 with carrier frequency of 26.5 GHz. The compensation results in an out-of-band noise reduction of 44 dB close to the carrier frequency. Furthermore, EVM improvements for NR signals are demonstrated.

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