Axel Flament | ISEN - Academia.edu (original) (raw)

Papers by Axel Flament

2006 13th IEEE International Conference on Electronics, Circuits and Systems, 2006

This paper presents a very high-speed delta-sigma modulator for achieving digital generation of r... more This paper presents a very high-speed delta-sigma modulator for achieving digital generation of radio-frequency signals. About 68 dB of ACLR (adjacent channel leakage ratio) is obtained on the 7.8 GS/s output of the delta-sigma modulator for WCDMA standard. This is achieved by using original concepts like borrow-save arithmetic, non-exact quantization and differential dynamic logic.

Analog Circuit Design, 2009

This paper presents an all-digital approach to the generation of the modulated radio-frequency ca... more This paper presents an all-digital approach to the generation of the modulated radio-frequency carrier and its application to a multimode transmitter in today’s communication systems and draws a possible picture of tomorrow’s systems. We will first analyze how digital transmitters will progressively replace their analog counterparts and what are the main issues associated with this trend. The combination of Δ​Σ modulation and digital mixing is proposed as an innovative approach enabling multimode operation of transmitters with low power consumption and chip area, easy configurability, and good performance. A 90 nm CMOS chip has been designed to demonstrate the feasibility of the concept and its potential in multimode transmitter architectures. Techniques such as redundant arithmetic and non-exact quantization are used in the high-speed Δ​Σ modulator implementation. Furthermore, approaches to antenna filtering using BAW filters and reconfigurable semi-digital RF FIR filters will be introduced. Finally, a review of recent outstanding transmitter designs will allow a comparison between the presented approach and architectures based on digital-to-RF conversion.

2008 4th European Conference on Circuits and Systems for Communications, 2008

... depends mainly on two parameters : the order of the noise-shaping filter and the ... B. Baseb... more ... depends mainly on two parameters : the order of the noise-shaping filter and the ... B. Baseband processing The baseband processing includes pulse shaping filters, half band filters, resampler and ... a selected channel (by using a CORDIC digital algorithm) [5]. For WCDMA, the IQ ...

2008 IEEE Radio Frequency Integrated Circuits Symposium, 2008

The presented digital RF signal generator in 90 nm CMOS uses 1-bit DeltaSigma modulation and targ... more The presented digital RF signal generator in 90 nm CMOS uses 1-bit DeltaSigma modulation and targets mobile communication terminals. A 50 MHz bandwidth centered on 1 GHz can be achieved when the circuit is clocked at 4 GHz. Signals up to 3 GHz can be synthesized when using the first image band. The peak output power into a 100 Omega

ESSCIRC 2008 - 34th European Solid-State Circuits Conference, 2008

ABSTRACT This paper presents a reconfigurable semi-digital RFFIR filter suitable for digital tran... more ABSTRACT This paper presents a reconfigurable semi-digital RFFIR filter suitable for digital transmitters using 1-bit DeltaSigma signal generation. A transmission line based 5-channel power combiner allows both increase of output power and programmable filtering of the signal. A prototype has been built with 65 nm CMOS and Integrated Passive Devices (IPD) technologies. The system exhibits a 14 dB power gain for a peak power of 17 dBm at 1.2 GHz and an attenuation of out-of band noise of up to 15 dB. CMOS and IPD chip size are respectively 2.05 mm2 and 17.78 mm2.

2009 16th IEEE International Conference on Electronics, Circuits and Systems - (ICECS 2009), 2009

ABSTRACT

2008 4th European Conference on Circuits and Systems for Communications, 2008

Digital generation of radio-frequency signals is a key concept of software defined radio. One of ... more Digital generation of radio-frequency signals is a key concept of software defined radio. One of the main difficulties for multi-standard transmitter design based on Delta-Sigma (∆Σ) modulators is to respect the different specifications in terms of out-of-band spurious emission. Focusing on the TX path of a UMTS/DCS1800 mobile phone, we propose hereinafter an efficient method aiming at synthesizing a complex 5th-order ∆Σ modulator which respects the targeted standards spurious specifications. The use of a complex noise transfer function allows a better optimization of noise shaping. In addition, this approach eases the reconfiguration of the modulator, and, it is a powerful tool for all order (real and complex) ∆Σ modulators synthesis, as it will be illustrated.

2009 Joint IEEE North-East Workshop on Circuits and Systems and TAISA Conference, 2009

This paper presents the first demonstration of a complete CMOS 90 nm digital RF signal generator ... more This paper presents the first demonstration of a complete CMOS 90 nm digital RF signal generator for wireless communication systems including a BAW (Bulk Acoustic Wave) based filter. A 1-bit delta-sigma signal generator is assembled with a BAW band pass filter for the UMTS TX-band at 1.95 GHz. The system satisfies UMTS specifications for ACPR and spurious emissions as defined in the IST MOBILIS project. The CMOS and BAW chip sizes are respectively 3.2 mm2 and 4.7 mm2.

2007 18th European Conference on Circuit Theory and Design, 2007

Digital generation of radio-frequency signals is a key concept of software defined radios. One of... more Digital generation of radio-frequency signals is a key concept of software defined radios. One of the main difficulties for multi-standard transmitter design based on delta-sigma (DeltaSigma) modulators is to respect the different specifications in terms of out-of-band spurious emission. Focusing on the TX path of a UMTS/DCS1800 phone, a 3rd order DeltaSigma modulator has been previously proposed by A. Frappe

Modeling and Measurement Methods for Acoustic Waves and for Acoustic Microdevices, 2013

This paper presents an all-digital radio transmitte r architecture including a very high-speed di... more This paper presents an all-digital radio transmitte r architecture including a very high-speed digital de lta-sigma (ΔΣ ) modulator. Implementation constraints of a 3 rd order modulator are detailed. To relax post-filtering req uirement, an original method for the synthesis of non-convention al modulators has been developed. Finally, design issu es for UMTS - GSM1800 are discussed.

IEEE Journal of Solid-State Circuits, 2009

An all-digital RF signal generator using DeltaSigma modulation and targeted at transmitters for m... more An all-digital RF signal generator using DeltaSigma modulation and targeted at transmitters for mobile communication terminals has been implemented in 90 nm CMOS. Techniques such as redundant logic and non-exact quantization allow operation at up to 4 GHz sample rate, providing a 50 MHz bandwidth at a 1 GHz center frequency. The peak output power into a 100 Omega diff.

This paper presents an all-digital radio transmitter architecture using high-speed digital delta-... more This paper presents an all-digital radio transmitter architecture using high-speed digital delta-sigma ( ! ! ! ! ) modulators and BAW filters with sharp selectivity. A keypoint in the architecture is the optimal design of the modulator's noise transfer function for the various targeted standards. Simulation results for a dual-standard UMTS-GSM1800 transmitter are presented.

International Journal of RF and Microwave Computer-Aided Engineering, 2011

2006 13th IEEE International Conference on Electronics, Circuits and Systems, 2006

This paper presents a very high-speed delta-sigma modulator for achieving digital generation of r... more This paper presents a very high-speed delta-sigma modulator for achieving digital generation of radio-frequency signals. About 68 dB of ACLR (adjacent channel leakage ratio) is obtained on the 7.8 GS/s output of the delta-sigma modulator for WCDMA standard. This is achieved by using original concepts like borrow-save arithmetic, non-exact quantization and differential dynamic logic.

Analog Circuit Design, 2009

This paper presents an all-digital approach to the generation of the modulated radio-frequency ca... more This paper presents an all-digital approach to the generation of the modulated radio-frequency carrier and its application to a multimode transmitter in today’s communication systems and draws a possible picture of tomorrow’s systems. We will first analyze how digital transmitters will progressively replace their analog counterparts and what are the main issues associated with this trend. The combination of Δ​Σ modulation and digital mixing is proposed as an innovative approach enabling multimode operation of transmitters with low power consumption and chip area, easy configurability, and good performance. A 90 nm CMOS chip has been designed to demonstrate the feasibility of the concept and its potential in multimode transmitter architectures. Techniques such as redundant arithmetic and non-exact quantization are used in the high-speed Δ​Σ modulator implementation. Furthermore, approaches to antenna filtering using BAW filters and reconfigurable semi-digital RF FIR filters will be introduced. Finally, a review of recent outstanding transmitter designs will allow a comparison between the presented approach and architectures based on digital-to-RF conversion.

2008 4th European Conference on Circuits and Systems for Communications, 2008

... depends mainly on two parameters : the order of the noise-shaping filter and the ... B. Baseb... more ... depends mainly on two parameters : the order of the noise-shaping filter and the ... B. Baseband processing The baseband processing includes pulse shaping filters, half band filters, resampler and ... a selected channel (by using a CORDIC digital algorithm) [5]. For WCDMA, the IQ ...

2008 IEEE Radio Frequency Integrated Circuits Symposium, 2008

The presented digital RF signal generator in 90 nm CMOS uses 1-bit DeltaSigma modulation and targ... more The presented digital RF signal generator in 90 nm CMOS uses 1-bit DeltaSigma modulation and targets mobile communication terminals. A 50 MHz bandwidth centered on 1 GHz can be achieved when the circuit is clocked at 4 GHz. Signals up to 3 GHz can be synthesized when using the first image band. The peak output power into a 100 Omega

ESSCIRC 2008 - 34th European Solid-State Circuits Conference, 2008

ABSTRACT This paper presents a reconfigurable semi-digital RFFIR filter suitable for digital tran... more ABSTRACT This paper presents a reconfigurable semi-digital RFFIR filter suitable for digital transmitters using 1-bit DeltaSigma signal generation. A transmission line based 5-channel power combiner allows both increase of output power and programmable filtering of the signal. A prototype has been built with 65 nm CMOS and Integrated Passive Devices (IPD) technologies. The system exhibits a 14 dB power gain for a peak power of 17 dBm at 1.2 GHz and an attenuation of out-of band noise of up to 15 dB. CMOS and IPD chip size are respectively 2.05 mm2 and 17.78 mm2.

2009 16th IEEE International Conference on Electronics, Circuits and Systems - (ICECS 2009), 2009

ABSTRACT

2008 4th European Conference on Circuits and Systems for Communications, 2008

Digital generation of radio-frequency signals is a key concept of software defined radio. One of ... more Digital generation of radio-frequency signals is a key concept of software defined radio. One of the main difficulties for multi-standard transmitter design based on Delta-Sigma (∆Σ) modulators is to respect the different specifications in terms of out-of-band spurious emission. Focusing on the TX path of a UMTS/DCS1800 mobile phone, we propose hereinafter an efficient method aiming at synthesizing a complex 5th-order ∆Σ modulator which respects the targeted standards spurious specifications. The use of a complex noise transfer function allows a better optimization of noise shaping. In addition, this approach eases the reconfiguration of the modulator, and, it is a powerful tool for all order (real and complex) ∆Σ modulators synthesis, as it will be illustrated.

2009 Joint IEEE North-East Workshop on Circuits and Systems and TAISA Conference, 2009

This paper presents the first demonstration of a complete CMOS 90 nm digital RF signal generator ... more This paper presents the first demonstration of a complete CMOS 90 nm digital RF signal generator for wireless communication systems including a BAW (Bulk Acoustic Wave) based filter. A 1-bit delta-sigma signal generator is assembled with a BAW band pass filter for the UMTS TX-band at 1.95 GHz. The system satisfies UMTS specifications for ACPR and spurious emissions as defined in the IST MOBILIS project. The CMOS and BAW chip sizes are respectively 3.2 mm2 and 4.7 mm2.

2007 18th European Conference on Circuit Theory and Design, 2007

Digital generation of radio-frequency signals is a key concept of software defined radios. One of... more Digital generation of radio-frequency signals is a key concept of software defined radios. One of the main difficulties for multi-standard transmitter design based on delta-sigma (DeltaSigma) modulators is to respect the different specifications in terms of out-of-band spurious emission. Focusing on the TX path of a UMTS/DCS1800 phone, a 3rd order DeltaSigma modulator has been previously proposed by A. Frappe

Modeling and Measurement Methods for Acoustic Waves and for Acoustic Microdevices, 2013

This paper presents an all-digital radio transmitte r architecture including a very high-speed di... more This paper presents an all-digital radio transmitte r architecture including a very high-speed digital de lta-sigma (ΔΣ ) modulator. Implementation constraints of a 3 rd order modulator are detailed. To relax post-filtering req uirement, an original method for the synthesis of non-convention al modulators has been developed. Finally, design issu es for UMTS - GSM1800 are discussed.

IEEE Journal of Solid-State Circuits, 2009

An all-digital RF signal generator using DeltaSigma modulation and targeted at transmitters for m... more An all-digital RF signal generator using DeltaSigma modulation and targeted at transmitters for mobile communication terminals has been implemented in 90 nm CMOS. Techniques such as redundant logic and non-exact quantization allow operation at up to 4 GHz sample rate, providing a 50 MHz bandwidth at a 1 GHz center frequency. The peak output power into a 100 Omega diff.

This paper presents an all-digital radio transmitter architecture using high-speed digital delta-... more This paper presents an all-digital radio transmitter architecture using high-speed digital delta-sigma ( ! ! ! ! ) modulators and BAW filters with sharp selectivity. A keypoint in the architecture is the optimal design of the modulator's noise transfer function for the various targeted standards. Simulation results for a dual-standard UMTS-GSM1800 transmitter are presented.

International Journal of RF and Microwave Computer-Aided Engineering, 2011