The Experts below are selected from a list of 5550 Experts worldwide ranked by ideXlab platform

Gee-kung Chang - One of the best experts on this subject based on the ideXlab platform.

  • a novel scheme to generate single sideband millimeter wave Signals by using low frequency Local Oscillator Signal
    IEEE Photonics Technology Letters, 2008
    Co-Authors: Jianjun Yu, Ting Wang, Mingfang Huang, Gee-kung Chang
    Abstract:

    We have proposed and experimentally demonstrated a novel scheme to generate optical millimeter-wave (mm-wave) Signals by using single-sideband modulation with low-frequency Local Oscillator (LO) Signals. In this architecture, by incorporating the proper dc bias of the modulator in central office, the optical mm-wave carriers are generated with two times frequency of the LO Signal while largely reducing the bandwidth requirement of the modulator. We quantify the optical carrier-to-sideband ratio (CSR) of downstream transmission in this radio-over-fiber (ROF) link and establish that the performance of the ROF system can be significantly improved when the optical Signals are transmitted at CSR equal to 0 dB.

  • centralized lightwave radio over fiber system with photonic frequency quadrupling for high frequency millimeter wave generation
    IEEE Photonics Technology Letters, 2007
    Co-Authors: Zhensheng Jia, Ting Wang, Gee-kung Chang
    Abstract:

    We have proposed a novel radio-over-fiber architecture to reduce the system cost at both central office (CO) and base station (BS). In this architecture, by incorporating the proper dc bias and optical filtering techniques in CO, the optical millimeter- wave (mm-wave) carriers are generated with four times frequency of the Local Oscillator Signal. The BS is simplified by using the separated optical carrier along with downlink mm-wave Signals to carry the upstream data. We have experimentally demonstrated optical mm-wave carrier generation up to 64-GHz, and both down- and upstream Signal delivery over 20 km fiber with 1-dB power penalty.

Albrecht Ingo Schmid - One of the best experts on this subject based on the ideXlab platform.

  • simultaneous and interleaved acquisition of nmr Signals from different nuclei with a clinical mri scanner
    Magnetic Resonance in Medicine, 2016
    Co-Authors: Martin Meyerspeer, Arthur W Magill, Andre Kuehne, Rolf Gruetter, Ewald Moser, Albrecht Ingo Schmid
    Abstract:

    PURPOSE: Modification of a clinical MRI scanner to enable simultaneous or rapid interleaved acquisition of Signals from two different nuclei. METHODS: A device was developed to modify the Local Oscillator Signal fed to the receive channel(s) of an MRI console. This enables external modification of the frequency at which the receiver is sensitive and rapid switching between different frequencies. Use of the device was demonstrated with interleaved and simultaneous 31 P and 1 H spectroscopic acquisitions, and with interleaved 31 P and 1 H imaging. RESULTS: Signal amplitudes and Signal-to-noise ratios were found to be unchanged for the modified system, compared with data acquired with the MRI system in the standard configuration. CONCLUSION: Interleaved and simultaneous 1 H and 31 P Signal acquisition was successfully demonstrated with a clinical MRI scanner, with only minor modification of the RF architecture. While demonstrated with 31 P, the modification is applicable to any detectable nucleus without further modification, enabling a wide range of simultaneous and interleaved experiments to be performed within a clinical setting.

Martin Meyerspeer - One of the best experts on this subject based on the ideXlab platform.

  • simultaneous and interleaved acquisition of nmr Signals from different nuclei with a clinical mri scanner
    Magnetic Resonance in Medicine, 2016
    Co-Authors: Martin Meyerspeer, Arthur W Magill, Andre Kuehne, Rolf Gruetter, Ewald Moser, Albrecht Ingo Schmid
    Abstract:

    PURPOSE: Modification of a clinical MRI scanner to enable simultaneous or rapid interleaved acquisition of Signals from two different nuclei. METHODS: A device was developed to modify the Local Oscillator Signal fed to the receive channel(s) of an MRI console. This enables external modification of the frequency at which the receiver is sensitive and rapid switching between different frequencies. Use of the device was demonstrated with interleaved and simultaneous 31 P and 1 H spectroscopic acquisitions, and with interleaved 31 P and 1 H imaging. RESULTS: Signal amplitudes and Signal-to-noise ratios were found to be unchanged for the modified system, compared with data acquired with the MRI system in the standard configuration. CONCLUSION: Interleaved and simultaneous 1 H and 31 P Signal acquisition was successfully demonstrated with a clinical MRI scanner, with only minor modification of the RF architecture. While demonstrated with 31 P, the modification is applicable to any detectable nucleus without further modification, enabling a wide range of simultaneous and interleaved experiments to be performed within a clinical setting.

Ting Wang - One of the best experts on this subject based on the ideXlab platform.

  • a novel scheme to generate single sideband millimeter wave Signals by using low frequency Local Oscillator Signal
    IEEE Photonics Technology Letters, 2008
    Co-Authors: Jianjun Yu, Ting Wang, Mingfang Huang, Gee-kung Chang
    Abstract:

    We have proposed and experimentally demonstrated a novel scheme to generate optical millimeter-wave (mm-wave) Signals by using single-sideband modulation with low-frequency Local Oscillator (LO) Signals. In this architecture, by incorporating the proper dc bias of the modulator in central office, the optical mm-wave carriers are generated with two times frequency of the LO Signal while largely reducing the bandwidth requirement of the modulator. We quantify the optical carrier-to-sideband ratio (CSR) of downstream transmission in this radio-over-fiber (ROF) link and establish that the performance of the ROF system can be significantly improved when the optical Signals are transmitted at CSR equal to 0 dB.

  • centralized lightwave radio over fiber system with photonic frequency quadrupling for high frequency millimeter wave generation
    IEEE Photonics Technology Letters, 2007
    Co-Authors: Zhensheng Jia, Ting Wang, Gee-kung Chang
    Abstract:

    We have proposed a novel radio-over-fiber architecture to reduce the system cost at both central office (CO) and base station (BS). In this architecture, by incorporating the proper dc bias and optical filtering techniques in CO, the optical millimeter- wave (mm-wave) carriers are generated with four times frequency of the Local Oscillator Signal. The BS is simplified by using the separated optical carrier along with downlink mm-wave Signals to carry the upstream data. We have experimentally demonstrated optical mm-wave carrier generation up to 64-GHz, and both down- and upstream Signal delivery over 20 km fiber with 1-dB power penalty.

A Tham - One of the best experts on this subject based on the ideXlab platform.

  • a 5 ghz direct conversion cmos transceiver
    IEEE Journal of Solid-state Circuits, 2003
    Co-Authors: Pengfei Zhang, T Nguyen, C Lam, D Gambetta, T Soorapanth, Baohong Cheng, S Hart, I Sever, T Bourdi, A Tham
    Abstract:

    A CMOS transceiver fully compliant with IEEE 802.11a in the unlicensed national information infrastructure (UNII) band (5.15-5.35 GHz) achieves a receiver sensitivity of -5 dBm for 64-QAM (quadrature amplitude modulation) with an error vector magnitude (EVM) of -29.3 dB. A single-sideband mixing technique for Local-Oscillator Signal generation avoids frequency pulling. Realized in 0.18-/spl mu/m CMOS and operating from 1.8-V power supply, the design consumes 171 mW in receive mode and 135 mW in transmit mode while occupying less than 13 mm/sup 2/.