The Experts below are selected from a list of 92454 Experts worldwide ranked by ideXlab platform
Ali M Niknejad - One of the best experts on this subject based on the ideXlab platform.
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design considerations for a direct digitally modulated wlan transmitter with integrated Phase Path and dynamic impedance modulation
IEEE Journal of Solid-state Circuits, 2013Co-Authors: Jiashu Chen, Lingkai Kong, Elad Alon, Ali M NiknejadAbstract:A 65-nm digitally modulated polar TX for WLAN 802.11g is fully integrated along with baseband digital filtering. The TX employs dynamic impedance modulation to improve efficiency at back-off powers. High-bandwidth Phase modulation is achieved efficiently with an open-loop architecture. Operating from 1.2-V/1-V supplies, the TX delivers 16.8 dBm average power at -28-dB EVM with 24.5% drain efficiency, 22% PAE, 19.3% system efficiency, and 247-mW power consumption including the entire on-chip TX chain; the noise floor is -125 dBm/Hz at 200-MHz offset without external filtering.
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a digitally modulated 2 4ghz wlan transmitter with integrated Phase Path and dynamic load modulation in 65nm cmos
International Solid-State Circuits Conference, 2013Co-Authors: Jiashu Chen, Lingkai Kong, Elad Alon, Philippe Cathelin, Ali M NiknejadAbstract:In order to support higher throughputs, the power consumption of 2-to-5GHz Wi-Fi transmitters (TXs) has been continuously rising, and has hence become increasingly problematic for mobile devices. To extend battery life, the TX must be efficient not only at peak power but also at backoff, due to the use of high Peak-to-Average-Power-Ratio (PAPR) OFDM modulation. Many recent works have aimed to enhance PA efficiency at back-off powers [1-4], but relatively few have integrated these techniques into a complete TX system. For example, previous designs employing digital polar or outphasing architectures often realized Phase modulation with off-chip instruments. Similarly, while good close-in spectral performance has been shown, far-out spectral images remain problematic for TXs where the PA itself is digitally modulated. Moreover, previous works often do not include overhead from components such as extra DC-DC converters (for multiple PA supplies) or did not implement on-chip matching networks (MN) and/or output baluns, all of which directly affect the overall efficiency of integrated CMOS PAs.
Yiying Shen - One of the best experts on this subject based on the ideXlab platform.
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a method for recovering maneuver targets spectra based on the algorithm of decontaminating ionospheric slow Phase Path disturbance
International Conference on Innovative Computing Information and Control, 2009Co-Authors: Jun Tang, Chengyu Hou, Yiying ShenAbstract:Both ionospheric slow Phase-Path disturbance and targets' maneuver will make the targets' echoes broaden in HF radar. Although their mechanism to spread the spectra is different, they are consistent on the view of the Phase of targets' echoes. Using the algorithm of ionospheric disturbance decontamination which has been successfully applied in practice, a method for recovering maneuver targets spectra has been presented in this paper. Results of experimental data of HF radar and meter-wave radar verify the correctness of such process. And they also show that the algorithm can effectively improve the quality of the targets spectra to improve the radar target detection and tracking performance.
Lirong Zheng - One of the best experts on this subject based on the ideXlab platform.
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the design of all digital polar transmitter based on adpll and Phase synchronized δσ modulator
IEEE Journal of Solid-state Circuits, 2012Co-Authors: Jian Chen, Liang Rong, Fredrik Jonsson, Geng Yang, Lirong ZhengAbstract:An improved architecture of polar transmitter (TX) is presented. The proposed architecture is digitally-intensive and mainly composed of an all-digital PLL (ADPLL) for Phase modulation, a 1-bit low-pass delta sigma ΔΣ modulator for envelop modulation, and a H-bridge class-D power amplifier (PA) for differential signaling. The ΔΣ modulator is clocked using the Phase modulated RF carrier to ensure Phase synchronization between the amplitude and Phase Path, and to guarantee the PA is switching at zero crossings of the output current. An on-chip pre-filter is used to reduce the parasitic capacitance from packages at the switch stage output. The high over sampling ratio of the ΔΣ modulator move quantization noise far away from the carrier frequency, ensuring good in-band performance and relax filter requirements. The on-chip filter also acts as impedance matching and differential to single-ended conversion. The measured digital transmitter consumes 58 mW from a 1-V supply at 6.8 dBm output power.
Jiashu Chen - One of the best experts on this subject based on the ideXlab platform.
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design considerations for a direct digitally modulated wlan transmitter with integrated Phase Path and dynamic impedance modulation
IEEE Journal of Solid-state Circuits, 2013Co-Authors: Jiashu Chen, Lingkai Kong, Elad Alon, Ali M NiknejadAbstract:A 65-nm digitally modulated polar TX for WLAN 802.11g is fully integrated along with baseband digital filtering. The TX employs dynamic impedance modulation to improve efficiency at back-off powers. High-bandwidth Phase modulation is achieved efficiently with an open-loop architecture. Operating from 1.2-V/1-V supplies, the TX delivers 16.8 dBm average power at -28-dB EVM with 24.5% drain efficiency, 22% PAE, 19.3% system efficiency, and 247-mW power consumption including the entire on-chip TX chain; the noise floor is -125 dBm/Hz at 200-MHz offset without external filtering.
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a digitally modulated 2 4ghz wlan transmitter with integrated Phase Path and dynamic load modulation in 65nm cmos
International Solid-State Circuits Conference, 2013Co-Authors: Jiashu Chen, Lingkai Kong, Elad Alon, Philippe Cathelin, Ali M NiknejadAbstract:In order to support higher throughputs, the power consumption of 2-to-5GHz Wi-Fi transmitters (TXs) has been continuously rising, and has hence become increasingly problematic for mobile devices. To extend battery life, the TX must be efficient not only at peak power but also at backoff, due to the use of high Peak-to-Average-Power-Ratio (PAPR) OFDM modulation. Many recent works have aimed to enhance PA efficiency at back-off powers [1-4], but relatively few have integrated these techniques into a complete TX system. For example, previous designs employing digital polar or outphasing architectures often realized Phase modulation with off-chip instruments. Similarly, while good close-in spectral performance has been shown, far-out spectral images remain problematic for TXs where the PA itself is digitally modulated. Moreover, previous works often do not include overhead from components such as extra DC-DC converters (for multiple PA supplies) or did not implement on-chip matching networks (MN) and/or output baluns, all of which directly affect the overall efficiency of integrated CMOS PAs.
Jun Tang - One of the best experts on this subject based on the ideXlab platform.
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a method for recovering maneuver targets spectra based on the algorithm of decontaminating ionospheric slow Phase Path disturbance
International Conference on Innovative Computing Information and Control, 2009Co-Authors: Jun Tang, Chengyu Hou, Yiying ShenAbstract:Both ionospheric slow Phase-Path disturbance and targets' maneuver will make the targets' echoes broaden in HF radar. Although their mechanism to spread the spectra is different, they are consistent on the view of the Phase of targets' echoes. Using the algorithm of ionospheric disturbance decontamination which has been successfully applied in practice, a method for recovering maneuver targets spectra has been presented in this paper. Results of experimental data of HF radar and meter-wave radar verify the correctness of such process. And they also show that the algorithm can effectively improve the quality of the targets spectra to improve the radar target detection and tracking performance.