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Author: search.filters.author.Somdunyakanok, MontriSubject: search.filters.subject.High-frequency

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    Log-domain all-pass based multiphase sinusoidal oscillator
    (2012-10-05)
    Prommee, Pipat
    ;
    Somdunyakanok, Montri
    This paper describes the design of a current-mode multiphase sinusoidal oscillator (MSO) based on log-domain all-pass network. The first order all-pass filter circuit is realized by first order all-pass filter. In each block of all-pass filter includes ten bipolar transistors and a grounded capacitor. The simulation of three-phase sinusoidal signal generator is carried out by SPICE. The 2.5V power supply is used for achieving the frequency from 700Hz - 70MHz by adjusting the bias currents. For bias currents 100 μA, the frequency of the signal is obtained around 7MHz and total harmonic distortion is measured around 1.5%. The three signal outputs of the proposed MSO are equally spaced in phase and amplitude. © 2012 IEEE.
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    Log-domain all-pass filter and its application to quadrature sinusoidal oscillator
    (2011-10-13)
    Prommee, Pipat
    ;
    Pattanatadapong, Thanate
    ;
    Somdunyakanok, Montri
    A realization of current-mode log-domain all-pass filter is proposed. The circuit is a direct realization of a first-order differential equation for obtaining the low-pass filter. The proposed all-pass filter is realized by using log-domain low-pass filter. The log-domain all-pass filters is realized by using only 10 NPN transistors and a grounded capacitor for achieving low-power and fast response. The frequency response and stage gain can be electronically tuned through bias currents. An application of proposed log-domain all-pass filter is a quadrature sinusoidal oscillator. The proposed oscillator is obtained by cascading two all-pass filters loop. A validated BJT model which is used in SPICE simulation operated from a single power supply as low as 2V. The proposed circuit is also suitable for high-frequency applications. SPICE simulation results confirm the theoretical results. © 2011 IEEE.
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    Quadrature sinusoidal oscillator based on log-domain high-pass and low-pass filters
    (2011-10-13)
    Prommee, Pipat
    ;
    Prapakorn, Nattawit
    ;
    Somdunyakanok, Montri
    A log-domain current-mode quadrature sinusoidal oscillator (QSO) based on low-pass (LP) and high-pass (HP) filters is presented. The log-domain QSO is realized by using only 18 NPN transistors and 2 grounded capacitors for achieving low-power and fast response. The proposed oscillator uses a cascade connecting the LP and HP which can be electronically tuned through bias current. Frequency of oscillation can be tuned over a wide-range with a low-power supply as 2V which is suitable for IC production. The power consumption is obtained around 5.5mW at 100μA of bias current. The oscillation frequency is controlled over four decades of frequency. The total harmonic distortion of QSO at 10.63MHz is obtained around 1.25%. The proposed circuit is suitable for high-frequency applications. PSpice simulation confirms the theoretical results. © 2011 IEEE.
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    Tunable current-mode log-domain universal filter
    (2010-08-31)
    Prommee, Pipat
    ;
    Somdunyakanok, Montri
    ;
    Angkeaw, Krit
    ;
    Dejhan, Kobchai
    This paper describes the design of a current-mode universal filter based on log-domain filtering concept. The circuit is a direct realization of a first-order differential equation for obtaining the two integrators loop structure. Lossless integrators are realized by log-domain lossy integrators. The proposed filter comprises only two grounded capacitors and sixteen transistors. Frequency response of the proposed filter can be instantaneously controlled over a very wide frequency range by controlling current. Quality factor is independently controlled by another current. It can be seen that the proposed circuit suites for high-frequency applications. A validated BJT model that used in simulation is operated by a single power supply as low as 2.5V. The wide-range frequency response is controlled over five decades of current controlled. ©2010 IEEE.
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    Current-mode multiphase sinusoidal oscillator based on log-domain filtering
    (2010-07-30)
    Prommee, Pipat
    ;
    Somdunyakanok, Montri
    This paper describes the design of a multiphase sinusoidal oscillator (MSO) based on log-domain filtering concept. The circuit is a direct realization of a first-order differential equation for obtaining the inverting lossy integrators. Each integrator comprises only a grounded capacitor and four transistors per phase. The proposed MSO can be instantaneously controlled over a very wide frequency range by controlling a current for oscillation frequency and oscillation condition which are indicated proposed MSO suitability in high-frequency communications. The power consumption is obtained around 5.5mW at 100μA of bias current based on 2.5V single power supply. The oscillation frequency is controlled over four decades of frequency. The total harmonic distortion of three-phases (11.5MHz) is obtained around 2.4%.