The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform

Farrokh Ayazi - One of the best experts on this subject based on the ideXlab platform.

  • An electronically temperature-compensated 427MHz low phase-noise AlN-on-Si micromechanical Reference Oscillator
    2010 IEEE Radio Frequency Integrated Circuits Symposium, 2010
    Co-Authors: Hossein Miri Lavasani, Farrokh Ayazi
    Abstract:

    This paper reports on the first demonstration of series tuning for lateral micromechanical Oscillators and its application in a temperature-compensated 427MHz AlN-on-Si Reference Oscillator. The sustaining amplifier is a 13mW tunable TIA implemented in 0.18μm CMOS that uses shunt-parasitic cancellation to increase the tuning by 12× to 810ppm. The tunable Oscillator along with a 2mW on-chip temperature compensation circuit has reduced the overall frequency drift to 70ppm in -10°C to 70°C. The phase-noise of the Oscillator reaches -82dBc/Hz at 1kHz offset with floor below -147dBc/Hz.

  • thin film piezoelectric on silicon resonators for high frequency Reference Oscillator applications
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2008
    Co-Authors: Reza Abdolvand, Hossein Miri Lavasani, G.k. Ho, Farrokh Ayazi
    Abstract:

    This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency Reference Oscillators. Low-motional impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble Reference Oscillators and the performance characteristics of the Oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the Oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is ~350 muW for an Oscillator operating at ~106 MHz. A passive temperature compensation method is also utilized bThis paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency Reference Oscillators. Low-motionalimpedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble Reference Oscillators and the performance characteristics of the Oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the Oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is ~350 muW for an Oscillator operating at ~106 MHz. A passive temperature compensation method is also utilized by including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/degC) temperature coefficient of frequency is obtained for an 82-MHz Oscillator.y including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/degC) temperature coefficient of frequency is obtained for an 82-MHz Oscillator.

  • A 500MHz low phase-noise AlN-on-silicon Reference Oscillator
    Proceedings of the Custom Integrated Circuits Conference, 2008
    Co-Authors: Hossein Miri Lavasani, Reza Abdolvand, Farrokh Ayazi
    Abstract:

    This paper presents a 496MHz low phase-noise Reference Oscillator using a high-Q lateral-mode AIN-on-Si micromechanical resonator that does not require DC voltage for operation. The sustaining amplifier consists of an inductorless high-gain CMOS transimpedance amplifier (TIA) that is optimized for low phase-noise. The resonator is designed to have a high quality factor in air (Q3800) with low motional impedance. The measured phase-noise at 1kHz offset is -92dBc/Hz with phase-noise floor below -147dBc/Hz (exceeding GSM phase-noise requirement by 2dB and 28d 15. respectively). 2007 IEEE.

  • Thin-film piezoelectric-on-silicon resonators for high-frequency Reference Oscillator applications
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2008
    Co-Authors: Reza Abdolvand, Gavin K. Ho, Hossein Miri Lavasani, Farrokh Ayazi
    Abstract:

    This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency Reference Oscillators. Low-motional-impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble Reference Oscillators and the performance characteristics of the Oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the Oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is approximately 350 microW for an Oscillator operating at approximately 106 MHz. A passive temperature compensation method is also utilized by including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/ degrees C) temperature coefficient of frequency is obtained for an 82-MHz Oscillator.

  • CICC - A 500MHz Low Phase-Noise A1N-on-Silicon Reference Oscillator
    2007 IEEE Custom Integrated Circuits Conference, 2007
    Co-Authors: Hossein Miri Lavasani, Reza Abdolvand, Farrokh Ayazi
    Abstract:

    This paper presents a 496 MHz low phase-noise Reference Oscillator using a high-Q lateral-mode AlN-on-Si micromechanical resonator that does not require DC voltage for operation. The sustaining amplifier consists of an inductorless high-gain CMOS transimpedance amplifier (TIA) that is optimized for low phase-noise. The resonator is designed to have a high quality factor in air (Q-3800) with low motional impedance. The measured phase-noise at 1 kHz offset is -92 dBc/Hz with phase-noise floor below -147 dBc/Hz (exceeding GSM phase-noise requirement by 2 dB and 28 dB, respectively).

Hossein Miri Lavasani - One of the best experts on this subject based on the ideXlab platform.

  • An electronically temperature-compensated 427MHz low phase-noise AlN-on-Si micromechanical Reference Oscillator
    2010 IEEE Radio Frequency Integrated Circuits Symposium, 2010
    Co-Authors: Hossein Miri Lavasani, Farrokh Ayazi
    Abstract:

    This paper reports on the first demonstration of series tuning for lateral micromechanical Oscillators and its application in a temperature-compensated 427MHz AlN-on-Si Reference Oscillator. The sustaining amplifier is a 13mW tunable TIA implemented in 0.18μm CMOS that uses shunt-parasitic cancellation to increase the tuning by 12× to 810ppm. The tunable Oscillator along with a 2mW on-chip temperature compensation circuit has reduced the overall frequency drift to 70ppm in -10°C to 70°C. The phase-noise of the Oscillator reaches -82dBc/Hz at 1kHz offset with floor below -147dBc/Hz.

  • thin film piezoelectric on silicon resonators for high frequency Reference Oscillator applications
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2008
    Co-Authors: Reza Abdolvand, Hossein Miri Lavasani, G.k. Ho, Farrokh Ayazi
    Abstract:

    This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency Reference Oscillators. Low-motional impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble Reference Oscillators and the performance characteristics of the Oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the Oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is ~350 muW for an Oscillator operating at ~106 MHz. A passive temperature compensation method is also utilized bThis paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency Reference Oscillators. Low-motionalimpedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble Reference Oscillators and the performance characteristics of the Oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the Oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is ~350 muW for an Oscillator operating at ~106 MHz. A passive temperature compensation method is also utilized by including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/degC) temperature coefficient of frequency is obtained for an 82-MHz Oscillator.y including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/degC) temperature coefficient of frequency is obtained for an 82-MHz Oscillator.

  • A 500MHz low phase-noise AlN-on-silicon Reference Oscillator
    Proceedings of the Custom Integrated Circuits Conference, 2008
    Co-Authors: Hossein Miri Lavasani, Reza Abdolvand, Farrokh Ayazi
    Abstract:

    This paper presents a 496MHz low phase-noise Reference Oscillator using a high-Q lateral-mode AIN-on-Si micromechanical resonator that does not require DC voltage for operation. The sustaining amplifier consists of an inductorless high-gain CMOS transimpedance amplifier (TIA) that is optimized for low phase-noise. The resonator is designed to have a high quality factor in air (Q3800) with low motional impedance. The measured phase-noise at 1kHz offset is -92dBc/Hz with phase-noise floor below -147dBc/Hz (exceeding GSM phase-noise requirement by 2dB and 28d 15. respectively). 2007 IEEE.

  • Thin-film piezoelectric-on-silicon resonators for high-frequency Reference Oscillator applications
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2008
    Co-Authors: Reza Abdolvand, Gavin K. Ho, Hossein Miri Lavasani, Farrokh Ayazi
    Abstract:

    This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency Reference Oscillators. Low-motional-impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble Reference Oscillators and the performance characteristics of the Oscillators are measured and discussed. Since the motional impedance of these devices is small, the transimpedance amplifier (TIA) in the Oscillator loop can be reduced to a single transistor and 3 resistors, a format that is very power-efficient. The lowest reported power consumption is approximately 350 microW for an Oscillator operating at approximately 106 MHz. A passive temperature compensation method is also utilized by including the buried oxide layer of the silicon-on-insulator (SOI) substrate in the structural resonant body of the device, and a very small (-2.4 ppm/ degrees C) temperature coefficient of frequency is obtained for an 82-MHz Oscillator.

  • CICC - A 500MHz Low Phase-Noise A1N-on-Silicon Reference Oscillator
    2007 IEEE Custom Integrated Circuits Conference, 2007
    Co-Authors: Hossein Miri Lavasani, Reza Abdolvand, Farrokh Ayazi
    Abstract:

    This paper presents a 496 MHz low phase-noise Reference Oscillator using a high-Q lateral-mode AlN-on-Si micromechanical resonator that does not require DC voltage for operation. The sustaining amplifier consists of an inductorless high-gain CMOS transimpedance amplifier (TIA) that is optimized for low phase-noise. The resonator is designed to have a high quality factor in air (Q-3800) with low motional impedance. The measured phase-noise at 1 kHz offset is -92 dBc/Hz with phase-noise floor below -147 dBc/Hz (exceeding GSM phase-noise requirement by 2 dB and 28 dB, respectively).

S.a. Diddams - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis of Optical Frequencies and Ultrastable Femtosecond Pulse Trains from an Optical Reference Oscillator
    Springer Series in OPTICAL SCIENCES, 2004
    Co-Authors: A. Bartels, T.m. Ramond, S.a. Diddams, L. Hollberg
    Abstract:

    Recently, atomic clocks based on optical frequency standards have been demonstrated [1,2]. A key element in these clocks is a femtosecond laser that downconverts the petahertz oscillation rate into countable ticks at 1 GHz. When compared to current microwave standards, these new optical clocks are expected to yield an improvement in stability and accuracy by roughly a factor of 1000. Furthermore, it is possible that the lowest noise microwave sources will soon be based on atomically-stabilized optical Oscillators that have their frequency converted to the microwave domain via a femtosecond laser. Here, we present tests of the ability of femtosecond lasers to transfer stability from an optical Oscillator to their repetition rates as well as to the associated broadband frequency comb. In a first experiment, we phase-lock two lasers to a stabilized laser diode and find that the relative timing jitter in their pulse trains can be on the order of 1 femtosecond in a 100 kHz bandwidth. It is important to distinguish this technique from previous work where a femtosecond laser has been stabilized to a microwave standard [3,4] or another femtosecond laser [5]. Furthermore, we extract highly stable microwave signals with a fractional frequency instability of 2×10−14 in 1 s by photodetection of the laser pulse trains. In a second experiment, we similarly phase-lock the femtosecond laser to an optical Oscillator with linewidth less than 1 Hz [6]. The precision with which we can make the femtosecond frequency comb track this Reference Oscillator is then tested by a heterodyne measurement between a second stable optical Oscillator and a mode of the frequency comb that is displaced 76 THz from the 1 Hz-wide Reference. From this heterodyne signal we place an upper limit of 150 Hz on the linewidth of the elements of the frequency comb, limited by the noise in the measurement itself.

  • Synthesis of ultrastable femtosecond pulse trains from an optical Reference Oscillator
    Postconference Digest Quantum Electronics and Laser Science 2003. QELS., 2003
    Co-Authors: A. Bartels, T.m. Ramond, S.a. Diddams, L. Hollberg
    Abstract:

    We phase-lock the repetition rates of two Ti:sapphire femtosecond lasers to an optical Reference Oscillator at their 456000th harmonic and achieve sub-femtosecond timing jitter. A system that can be continuously stabilized for periods approaching one day is demonstrated.

  • mode locked laser pulse trains with subfemtosecond timing jitter synchronized to an optical Reference Oscillator
    Optics Letters, 2003
    Co-Authors: A Bartels, T.m. Ramond, S.a. Diddams, L Hollberg
    Abstract:

    We independently phase lock the repetition rates of two femtosecond lasers at their ≈456,000th harmonic to a common optical Oscillator. The timing jitter of each individual laser relative to the optical Reference is only 0.45 fs in a 100-Hz bandwidth. Our method takes advantage of the tremendous leverage that is possible when stability is transferred from the optical to the microwave domain. The low timing jitter is commensurate with the independently measured fractional frequency instability in the repetition rates of ≤2.3×10-15 in 1-s averaging time, limited by the measurement system. The microwave signals at 1 GHz that are extracted by photodetection of the pulse trains have a 10-times-greater instability, confirming the presence of excess noise in the photodetection.

T.m. Ramond - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis of Optical Frequencies and Ultrastable Femtosecond Pulse Trains from an Optical Reference Oscillator
    Springer Series in OPTICAL SCIENCES, 2004
    Co-Authors: A. Bartels, T.m. Ramond, S.a. Diddams, L. Hollberg
    Abstract:

    Recently, atomic clocks based on optical frequency standards have been demonstrated [1,2]. A key element in these clocks is a femtosecond laser that downconverts the petahertz oscillation rate into countable ticks at 1 GHz. When compared to current microwave standards, these new optical clocks are expected to yield an improvement in stability and accuracy by roughly a factor of 1000. Furthermore, it is possible that the lowest noise microwave sources will soon be based on atomically-stabilized optical Oscillators that have their frequency converted to the microwave domain via a femtosecond laser. Here, we present tests of the ability of femtosecond lasers to transfer stability from an optical Oscillator to their repetition rates as well as to the associated broadband frequency comb. In a first experiment, we phase-lock two lasers to a stabilized laser diode and find that the relative timing jitter in their pulse trains can be on the order of 1 femtosecond in a 100 kHz bandwidth. It is important to distinguish this technique from previous work where a femtosecond laser has been stabilized to a microwave standard [3,4] or another femtosecond laser [5]. Furthermore, we extract highly stable microwave signals with a fractional frequency instability of 2×10−14 in 1 s by photodetection of the laser pulse trains. In a second experiment, we similarly phase-lock the femtosecond laser to an optical Oscillator with linewidth less than 1 Hz [6]. The precision with which we can make the femtosecond frequency comb track this Reference Oscillator is then tested by a heterodyne measurement between a second stable optical Oscillator and a mode of the frequency comb that is displaced 76 THz from the 1 Hz-wide Reference. From this heterodyne signal we place an upper limit of 150 Hz on the linewidth of the elements of the frequency comb, limited by the noise in the measurement itself.

  • Synthesis of ultrastable femtosecond pulse trains from an optical Reference Oscillator
    Postconference Digest Quantum Electronics and Laser Science 2003. QELS., 2003
    Co-Authors: A. Bartels, T.m. Ramond, S.a. Diddams, L. Hollberg
    Abstract:

    We phase-lock the repetition rates of two Ti:sapphire femtosecond lasers to an optical Reference Oscillator at their 456000th harmonic and achieve sub-femtosecond timing jitter. A system that can be continuously stabilized for periods approaching one day is demonstrated.

  • mode locked laser pulse trains with subfemtosecond timing jitter synchronized to an optical Reference Oscillator
    Optics Letters, 2003
    Co-Authors: A Bartels, T.m. Ramond, S.a. Diddams, L Hollberg
    Abstract:

    We independently phase lock the repetition rates of two femtosecond lasers at their ≈456,000th harmonic to a common optical Oscillator. The timing jitter of each individual laser relative to the optical Reference is only 0.45 fs in a 100-Hz bandwidth. Our method takes advantage of the tremendous leverage that is possible when stability is transferred from the optical to the microwave domain. The low timing jitter is commensurate with the independently measured fractional frequency instability in the repetition rates of ≤2.3×10-15 in 1-s averaging time, limited by the measurement system. The microwave signals at 1 GHz that are extracted by photodetection of the pulse trains have a 10-times-greater instability, confirming the presence of excess noise in the photodetection.

D. Kasperkovitz - One of the best experts on this subject based on the ideXlab platform.

  • A low-phase-noise Reference Oscillator with integrated pMOS varactors for digital satellite receivers
    IEEE Journal of Solid-State Circuits, 2000
    Co-Authors: J.d. Van Der Tang, D. Kasperkovitz
    Abstract:

    A low-phase-noise LC Reference Oscillator (RO) for use in digital satellite receivers is described. This RO is an essential building block of a double-loop wide-band tuning system that reduces the phase noise of integrated quadrature voltage-controlled Oscillators (VCOs) required for zero-IF receivers. In order to achieve a high degree of integration the RO is implemented using integrated varactors. Three varactor options which are available in a standard 11-GHz f/sub t/ bipolar technology are investigated: the p-n junction of an NPN, an active varactor circuit, and a pMOS varactor. Experimental results show that the integrated pMOS varactor combined with external inductors is the preferred choice to implement the resonator of the low-phase-noise RO. The achieved tuning range is 225-310 MHz. Carrier-to-noise levels of more than 87 dBc/Hz at 10-kHz offset are measured. The performance is realized with a RO dissipation of 14 mW at a supply voltage of 3.5 V.

  • Low phase noise Reference Oscillator with integrated PMOS varactors for digital satellite receivers
    ICECS'99. Proceedings of ICECS '99. 6th IEEE International Conference on Electronics Circuits and Systems (Cat. No.99EX357), 1999
    Co-Authors: J. Van Der Tang, D. Kasperkovitz
    Abstract:

    For the first time, a low phase noise Reference Oscillator with integrated PMOS varactors is realized. Other integrated varactor options are qualitatively analyzed, and will be shown to fall short for application in a Reference Oscillator. Carrier to noise levels of 87 dBc/Hz @ 10 kHz offset and better are measured over a tuning range of 225 MHz to 310 MHz. Power supply voltage is 3.5 V and measured dissipation 14 mW. The design is optimized for use in zero-IF digital satellite front-ends which have a double loop tuning system. In double loop architectures a relatively noisy on-chip I/Q RC Oscillator is wideband locked to a clean Reference Oscillator to achieve phase noise levels sufficiently low for QPSK reception. A low cost implementation of the Reference Oscillator is realized, since only the coils of the Reference Oscillator are off-chip.