Digital Modulator with Bandpass Delta-Sigma Modulator

Sommarek, J.; Vankka, Jouko; Ketola, J.; Lindeberg, J.; Halonen, K.

doi:10.1007/s10470-005-6573-z

Cited by 5 publications

(2 citation statements)

References 10 publications

(10 reference statements)

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“…Band pass (BP) simga-delta (6' DACs have become an appealing option for full digital transceivers recently [1][2][3][4][5][6][7][8][9] because of their advantages over the Nyquist rate DACs. First, the requirements on the reconstruction filter are considerably reduced because the alias image is shifted far away from the signal band due to the high over-sampling-ratio (OSR) in BP6'DAC.…”

Section: Introductionmentioning

confidence: 99%

A 4th order band pass sigma-delta modulator using carry-save for digital IF quadrature modulator

Huang

Zhang

Ling

et al. 2012

2012 IEEE 14th International Conference on Communication Technology

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This paper presents a digital intermediate frequency (IF) quadrature modulator realized by a single-bit band pass sigma-delta DAC, in which a pair of single-bit-low-pass sigmadelta digital modulators is used to share the computation for doubling the speed. Fractional-delay interpolation filters are added before the sigma-delta modulators to adjust the interleaved timing relationship between the IQ paths. Carry-save algorithm is used to increase the computation speed in both sigma-delta modulators and interpolation filters, which leads to a speed improvement with little area overhead. The simulation results show that the proposed design can realize a single bit 4th order band pass sigma-delta DAC whose sampling frequency reach hundreds Mhz, and whose SFDR is up to 65 dB.

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Section: Introductionmentioning

confidence: 99%

A 4th order band pass sigma-delta modulator using carry-save for digital IF quadrature modulator

Huang

Zhang

Ling

et al. 2012

2012 IEEE 14th International Conference on Communication Technology

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“…As a cornerstone of SDR, all-digital RF transceiver based on delta-sigma modulation has attracted intensive research interest due to its low cost and flexibility to accommodate multiband multi-RAT operations. Both transmitter [30]- [52] and receiver [53]- [59] designs have been reported, and various delta-sigma modulators, including lowpass [30], [32]- [34], [36]- [39], [41]- [45], [47], [48], bandpass [31], [35], and multiband [40], [49]- [52] have been demonstrated. To relax the FPGA speed requirement, several time-interleaving or parallel processing techniques are also presented [38], [39], [43]- [45], [47], [48].…”

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confidence: 99%

Delta-Sigma Modulation for Next Generation Fronthaul Interface

Wang

Jia

Campos

et al. 2019

J. Lightwave Technol.

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A new function split option for the next generation fronthaul interface (NGFI) is demonstrated based on all-digital RF transmitter using bandpass delta-sigma modulation. Different from other low layer split (LLS) options, such as option 6 (MAC-PHY), 7 (high-low PHY), and 8 (CPRI), the proposed option 9 implements RF functions in the digital domain, and splits within the RF layer, with high-RF layer centralized in the distributed unit (DU) and low-RF layer distributed in remote radio units (RRUs). A proof-of-concept all-digital RF transmitter based on real-time delta-sigma modulation is implemented using a Xilinx Virtex-7 FPGA. A 5-GSa/s delta-sigma modulator is demonstrated to encode LTE/5G signals with bandwidth up to 252 MHz and modulation format up to 1024-QAM to a 5-Gb/s OOK signal, which is transmitted over 30-km single-mode fiber from DU to RRU. To relax the FPGA speed requirement, a 32-pipeline architecture is designed. Two-carrier aggregation of 5G and 14-carrier aggregation of LTE signals are demonstrated with error vector magnitude (EVM) performance satisfying the 3GPP specifications. Compared with option 8 (CPRI), although the proposed option 9 split occurs at a lower level, it offers improved spectral efficiency and reduced NGFI data rate than CPRI. Moreover, other LLS options, such as 6, 7, and 8, all require a complete RF layer implemented in the analog domain at remote cell sites; whereas option 9 realizes high-RF layer in the digital domain at DU, and eliminates the need of analog RF devices, such as DAC, local oscillator and mixer at RRU, which not only makes low-cost, energy-efficient, and small-footprint cell sites possible for the wide deployment of small cells, but also paves the road toward software defined radio (SDR) and virtualization of DU and RRU for improved compatibility and reconfigurability among multiple radio access technologies (multi-RATs). Given its centralized architecture and deterministic latency, option 9 is suitable for radio coordination applications, and has potential in low-frequency narrowband scenarios with cost, power, and/or size sensitive cell sites, such as massive machine type communication (mMTC) and narrowband internet of things (NB-IoT). Index Terms-All-digital RF transmitter, delta-sigma modulation, fronthaul, NGFI, software defined radio. I. INTRODUCTION T HE emerging video-intensive and bandwidth-consuming services, e.g., virtual reality, augmented reality, immersive applications, are driving the explosive growth of mobile data traffic [1]-[3], making radio access networks (RAN) become

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Class-S power amplifier concept for mobile communications in rural areas with concurrent transmission at 450 MHz and 900 MHz

Schmidt

Digel

Berroth

2011

2011 IEEE International Conference on Microwaves, Communications, Antennas and Electronic Systems (COMCAS 2011)

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An 15th order bandpass delta-sigma modulator for class-S power amplifiers is presented. The modulator is based on a third order low pass prototype which is designed to meet the requirements for signal-to-noise ratio (SNR) of major mobile communication standards in a bandwidth of around 30 MHz.The transform z −1 → z −5 leads to a repetition of the low pass notch in the noise transfer function (NTF) at frequencies f = n/5fs, n = 1, 2, 3, 4, 5, . . . . Apart from sinc filtering due to rectangular output pulses the NTF shape is equal in all frequency bands. The two lower frequency bands at f = 1/5fs, 2/5fs are independent from each other and can be used for concurrent transmission in the 450 MHz and 900 MHz band.The paper investigates the modulator with respect to the signal to noise ratio, the stability and the coding efficiency versus input amplitudes of tones in both frequency bands.

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Digital Modulator with Bandpass Delta-Sigma Modulator

Cited by 5 publications

References 10 publications

A 4th order band pass sigma-delta modulator using carry-save for digital IF quadrature modulator

A 4th order band pass sigma-delta modulator using carry-save for digital IF quadrature modulator

Delta-Sigma Modulation for Next Generation Fronthaul Interface

Class-S power amplifier concept for mobile communications in rural areas with concurrent transmission at 450 MHz and 900 MHz

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