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Johansson, Ted
Publications (10 of 22) Show all publications
Haque, M. F., Pasha, M. T. & Johansson, T. (2019). Power-efficient aliasing-free PWM transmitter. IET Circuits, Devices & Systems, 13(3), 273-278
Open this publication in new window or tab >>Power-efficient aliasing-free PWM transmitter
2019 (English)In: IET Circuits, Devices & Systems, ISSN 1751-858X, E-ISSN 1751-8598, Vol. 13, no 3, p. 273-278Article in journal (Refereed) Published
Abstract [en]

Linearity and efficiency are important parameters in determining the performance of any wireless transmitter. Pulse-width modulation (PWM) based transmitters offer high efficiency but suffer from low linearity due to image and aliasing distortions. Although the problem of linearity can be addressed by using an aliasing-free PWM (AF-PWM), these transmitters have a lower efficiency as they can only use linear power amplifiers (PAs). Moreover, an all-digital implementation of such transmitters is not possible. The aliasing-compensated PWM transmitter (AC-PWMT) has a higher efficiency due to the use of switch-mode PAs (SMPAs) but uses outphasing to eliminate image and aliasing distortions and requires a larger silicon area. In this study, the authors propose a novel transmitter that eliminates both aliasing and image distortions while using a single SMPA. The transmitter can be implemented using all-digital techniques and achieves a higher efficiency as compared to both AF-PWM and AC-PWM based transmitters. Measurement results show an improvement of 11.3, 7.2, and 4.3 dBc in the ACLR as compared to the carrier-based PWM transmitter (C-PWMT), AF-PWMT, and AC-PWMT, respectively. The efficiency of the proposed transmitter is similar to that of C-PWMT, which is an improvement of 5% over AF-PWMT.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2019
Keywords
all-digital implementation;aliasing-free PWM;wireless transmitter;switch-mode PA;AC-PWM based transmitters;carrier-based PWM transmitter;power-efficient aliasing-free PWM transmitter;Si;aliasing distortions;aliasing-compensated PWM transmitter;pulse-width modulation based transmitters;linear power amplifiers;C-PWMT;AF-PWM;silicon area;
National Category
Signal Processing Computer Vision and Robotics (Autonomous Systems)
Identifiers
urn:nbn:se:liu:diva-156307 (URN)10.1049/iet-cds.2018.5011 (DOI)000470680000002 ()
Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2019-07-03Bibliographically approved
Ul Haque, M. F., Touqir Pasha, M., Malik, T. & Johansson, T. (2018). A Comparison of Polar and Quadrature RF-PWM. In: 2018 IEEE NORDIC CIRCUITS AND SYSTEMS CONFERENCE (NORCAS): NORCHIP AND INTERNATIONAL SYMPOSIUM OF SYSTEM-ON-CHIP (SOC): . Paper presented at 4th IEEE Nordic Circuits and Systems Conference (NORCAS) / NORCHIP and International Symposium of System-on-Chip (SoC), Tallinn, Estonia, Oct 30-31 2018. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>A Comparison of Polar and Quadrature RF-PWM
2018 (English)In: 2018 IEEE NORDIC CIRCUITS AND SYSTEMS CONFERENCE (NORCAS): NORCHIP AND INTERNATIONAL SYMPOSIUM OF SYSTEM-ON-CHIP (SOC), Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper, Published paper (Refereed)
Abstract [en]

All-digital implementations of PWM-based wireless transmitters are gaining popularity. Unlike baseband PWM, RF-PWM has relaxed filtering requirements and is preferred due to a smaller chip size. This paper is aimed to highlight the differences between polar and quadrature implementations of RF-PWM-based transmitters. Using mathematical models and simulations, performance of the two implementations is compared. The mathematical analysis indicates that the quadrature implementation is expected to have higher quantization noise compared to the polar because of the shorter duty cycles at maximum amplitude. The simulations, using a 10 MHz LTE uplink signal at 2 GHz carrier frequency, confirm this and also show the effect of RF pulse swallowing on the error vector magnitude (EVM).

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
Polar RF-PWM; Quadrature RF-PWM; All digital transmitter; LTE
National Category
Signal Processing
Identifiers
urn:nbn:se:liu:diva-156226 (URN)10.1109/NORCHIP.2018.8573456 (DOI)000462188200007 ()9781538676561 (ISBN)9781538676578 (ISBN)
Conference
4th IEEE Nordic Circuits and Systems Conference (NORCAS) / NORCHIP and International Symposium of System-on-Chip (SoC), Tallinn, Estonia, Oct 30-31 2018
Available from: 2019-04-09 Created: 2019-04-09 Last updated: 2019-04-23
Touqir Pasha, M., Haque, M. F., Ahmad, J. & Johansson, T. (2018). An All-Digital Polar PWM Transmitter. In: : . Paper presented at Gigahertz 2018 symposium, Lund, Sweden, May 24-25, 2018.
Open this publication in new window or tab >>An All-Digital Polar PWM Transmitter
2018 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-156476 (URN)
Conference
Gigahertz 2018 symposium, Lund, Sweden, May 24-25, 2018
Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-04-23Bibliographically approved
Johansson, T., Morales Chacon, O. A. & Flink, T. (2018). Digital predistortion with bandwidth limitations for a 28 nm WLAN 802.11ac transmitter. In: : . Paper presented at Gigahertz 2018 symposium, Lund, Sweden, May 24-25, 2018.
Open this publication in new window or tab >>Digital predistortion with bandwidth limitations for a 28 nm WLAN 802.11ac transmitter
2018 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-156478 (URN)
Conference
Gigahertz 2018 symposium, Lund, Sweden, May 24-25, 2018
Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-05-13Bibliographically approved
Ul Haque, M. F., Johansson, T. & Liu, D. (2016). Large dynamic range PWM transmitter. In: : . Paper presented at Swedish Microwave Days - GigaHertz and AntennEMB and the GigaHertz Symposium ,15-16 Mars, 2016.Konsert & Kongress Center in Linköping (pp. 34). Linkoping
Open this publication in new window or tab >>Large dynamic range PWM transmitter
2016 (English)Conference paper, Oral presentation with published abstract (Other (popular science, discussion, etc.))
Place, publisher, year, edition, pages
Linkoping: , 2016
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-127998 (URN)
Conference
Swedish Microwave Days - GigaHertz and AntennEMB and the GigaHertz Symposium ,15-16 Mars, 2016.Konsert & Kongress Center in Linköping
Available from: 2016-05-16 Created: 2016-05-16 Last updated: 2016-05-23
Haque, M. F., Johansson, T. & Liu, D. (2015). Combined RF and Multiphase PWM Transmitter. In: 2015 European Conference on Circuit Theory and Design (ECCTD): . Paper presented at 2015 European Conference on Circuit Theory and Design (ECCTD), Trondheim, Norway, August 24-26, 2015 (pp. 264-267). IEEE
Open this publication in new window or tab >>Combined RF and Multiphase PWM Transmitter
2015 (English)In: 2015 European Conference on Circuit Theory and Design (ECCTD), IEEE , 2015, p. 264-267Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents two novel transmitter architectures based on the combination of radio-frequency pulse-width modulation and multiphase pulse-width modulation. The proposed transmitter architectures provide good amplitude resolution and large dynamic range at high carrier frequency, which is problematic with existing radio-frequency pulse-width modulation based transmitters. They also have better power efficiency and smaller chip area compared to multiphase pulse-width modulation based transmitters.

Place, publisher, year, edition, pages
IEEE, 2015
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-122703 (URN)10.1109/ECCTD.2015.7299999 (DOI)000380498200001 ()978-1-4799-9877-7 (ISBN)
Conference
2015 European Conference on Circuit Theory and Design (ECCTD), Trondheim, Norway, August 24-26, 2015
Available from: 2015-11-16 Created: 2015-11-16 Last updated: 2017-01-18Bibliographically approved
Haque, M. F., Johansson, T. & Liu, D. (2015). Combined RF and Multiphase PWM Transmitter. In: : . Paper presented at Swedish System on Chip Conference (SSoCC'15), Göteborg, Sweden, May 4-5 2015.
Open this publication in new window or tab >>Combined RF and Multiphase PWM Transmitter
2015 (English)Conference paper, Published paper (Other academic)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-122711 (URN)
Conference
Swedish System on Chip Conference (SSoCC'15), Göteborg, Sweden, May 4-5 2015
Available from: 2015-11-17 Created: 2015-11-17 Last updated: 2015-11-30Bibliographically approved
Haque, M. F., Johansson, T. & Liu, D. (2015). Modified Band-limited Pulse-Width Modulated Polar Transmitter. In: : . Paper presented at 15th International Symposium on Microwave and Optical Technology (ISMOT 2015), Dresden, Germany, June 29-July 1 2015.
Open this publication in new window or tab >>Modified Band-limited Pulse-Width Modulated Polar Transmitter
2015 (English)Conference paper, Published paper (Other academic)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-122702 (URN)
Conference
15th International Symposium on Microwave and Optical Technology (ISMOT 2015), Dresden, Germany, June 29-July 1 2015
Available from: 2015-11-16 Created: 2015-11-16 Last updated: 2015-11-30Bibliographically approved
Ul Haque, M. F., Johansson, T. & Liu, D. (2015). Power Efficienct Band-limited Pulse Width Modulated Transmitter. In: : . Paper presented at Swedish System on Chip Conference (SSoCC 2015) in Goteborg. 4-5 maj 2015, Novotel Hotel, Göteborg. Gothenburg
Open this publication in new window or tab >>Power Efficienct Band-limited Pulse Width Modulated Transmitter
2015 (English)Conference paper, Oral presentation only (Other (popular science, discussion, etc.))
Place, publisher, year, edition, pages
Gothenburg: , 2015
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-127999 (URN)
Conference
Swedish System on Chip Conference (SSoCC 2015) in Goteborg. 4-5 maj 2015, Novotel Hotel, Göteborg
Available from: 2016-05-16 Created: 2016-05-16 Last updated: 2016-05-23
Touqir Pasha, M., Johansson, T. & Vesterbacka, M. (2014). A novel technique to reduce the supply sensitivity of CMOS ring oscillators.
Open this publication in new window or tab >>A novel technique to reduce the supply sensitivity of CMOS ring oscillators
2014 (English)Manuscript (preprint) (Other academic)
Abstract [en]

A technique to abbreviate the supply sensitivity of CMOS ring oscillators is presented. By switching the power source from the noisy power supply to a battery during sensitive zero crossings the noise performance of the ring oscillator is improved. The proposed technique can be used in conjunction with other regulation techniques to enhance the performance of ring oscillators in phase locked loops. The proposed switching circuit using a pseudo differential ring oscillator are designed in a 65 nm CMOS process to demonstrate the viability of the proposed scheme in deep submicron process with reduced voltage headroom. At 2 GHz the outputclock exhibits a jitter of less than 14 ps while subjected to a 500 mV noise tone at 500 MHz.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-113280 (URN)
Available from: 2015-01-14 Created: 2015-01-14 Last updated: 2018-09-17
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