Chaichana, Amornchai

Preferred name

Alternative Name

Chaichana, Amonchai

Chaichana, Amornchia

Main Affiliation

School of Industrial Education and Technology

amornchai.ch@kmitl.ac.th

Now showing 1 - 7 of 7

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Single commercially available ic-based electronically controllable voltage-mode first-order multifunction filter with complete standard functions and low output impedance
(2021-11-01)
Jaikla, Winai
;
Buakhong, Unchittha
;
Siripongdee, Surapong
;
Khateb, Fabian
;
Sotner, Roman
This paper presents the design of a voltage-mode three-input single-output multifunction first-order filter employing commercially available LT1228 IC for easy verification of the proposed circuit by laboratory measurements. The proposed filter is very simple, consisting of a single LT1228 as an active device with two resistors and one capacitor. The output voltage node is low impedance, resulting in an easy cascade-ability with other voltage-mode configurations. The proposed filter provides four filter responses: low-pass filter (LP), high-pass filter (HP), inverting all-pass filter (AP−), and non-inverting all-pass filter (AP+) in the same circuit configuration. The selection of output filter responses can be conducted without additional inverting or double gains, which is easy to be controlled by the digital method. The control of pole frequency and phase response can be conducted electronically through the bias current (I<inf>B</inf>). The matching condition during tuning the phase response with constant voltage gain is not required. Moreover, the pass-band voltage gain of the LP and HP functions can be controlled by adjusting the value of resistors without affecting the pole frequency and phase response. Additionally, the phase responses of the AP filters can be selected as both lagging or leading phase responses. The parasitic effects on the filtering performances were also analyzed and studied. The performances of the proposed filter were simulated and experimented with a ±5 V voltage supply. For the AP+ experimental result, the leading phase response for 1 kHz to 1 MHz frequency changed from 180 to 0 degrees. For the AP− experimental result, the lagging phase response for 1 kHz to 1 MHz frequency changed from 0 to −180 degrees. The design of the quadrature oscillator based on the proposed first-order filter is also included as an application example.
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A New Method to Synthesise the Sinusoidal Oscillator Based on Series Negative Resistance-Capacitance and its Implementation Using a Single Commercial IC, LT1228
(2023-01-01)
Kulapong, Worawut
;
Jaikla, Winai
;
Siripongdee, Surapong
;
Sotner, Roman
;
Suwanjan, Peerawut
An alternative method for synthesising the sinusoidal oscillator based on series negative resistance-capacitance is presented in this paper. The proposed topology is constructed with the series negative resistance-capacitance circuit connected in parallel with a grounded resistor and capacitor. To validate the proposed method, a new grounded series negative resistance-capacitance simulator is also proposed as a subcircuit for synthesising the sinusoidal oscillator. The series negative resistance-capacitance simulator is based on a commercially available integrated circuit (IC), LT1228. The equivalent negative resistance and equivalent negative capacitance can be adjusted electronically using an external DC bias current. The sinusoidal oscillator that is synthesised using the proposed method consists of a single LT1228, two capacitors, and three resistors. The frequency and the condition of the oscillation are orthogonally adjusted. Also, the condition of oscillation is electronically controlled. The amplitude of the sinusoidal waveform is adjustable. In addition, the output voltage node of the proposed oscillator has a low impedance, which allows it to connect to other circuits without using an additional buffer. Both PSPICE simulation and experiment are used to validate the proposed circuits.
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Voltage-Controlled Sinusoidal Oscillator Using Commercially Available ICs with Amplitude Adjustability and Its Application to FM and FSK Modulations for Transmission and Processing of Identified Low-Frequency Signals
(2026-04-01)
Suwanjan, Peerawut
;
Adhan, Suchin
;
Chaichana, Amornchai
;
Sotner, Roman
;
Nramat, Wichai
This paper presents a new voltage-controlled sinusoidal oscillator employing only two commercially available LT1228 integrated circuits, four resistors, and two capacitors. The proposed oscillator provides independent control of oscillation frequency and oscillation condition, as well as adjustable output amplitude, while maintaining low output impedance without requiring additional active components. The oscillation frequency is electronically and linearly tuned via the LT1228 bias current or control voltage. Experimental results confirm the practicality of the design: The proposed VCO achieves a wide linear tuning range from 9.25 kHz to 837.2 kHz, THD below 2.55%, and phase noise of –73.35 dBc/Hz at a 1 kHz offset for a 237.8 kHz carrier. The amplitude of the sinusoidal output is adjustable from 0.48 Vp-p to 6.64 Vp-p. In addition, the proposed VCO is successfully applied to FM and FSK modulation for low-frequency signal transmission, and the FM demodulation test yields a recovered sawtooth signal with an SNR of 34.51 dB. Compared with existing LT1228-based oscillators, the proposed circuit achieves 25% lower power consumption (149 mW) and reduces the number of ICs required while improving functional versatility. These results validate the effectiveness and novelty of the proposed LT1228-based design.
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Design of Electronically Controllable Quadrature Sinusoidal Oscillator with Linear Control of Frequency
(2019-12-01)
Jaikla, Winai
;
Suwanjan, Peerawut
;
Chaichana, Amornchai
;
Sotner, Roman
In this paper, the design of sinusoidal oscillator which generates two output voltages with 90° degree phase difference is presented. The design procedure is started from the function block diagram to proposed oscillator using commercially available ICs. The proposed oscillator is constructed from three OTAs, one voltage summing circuit, one grounded resistor and two grounded capacitors. The frequency of the generated sinusoidal waveform is electronically and linearly controlled without disturbing the condition for oscillating of the system. With this feature, the proposed oscillator is used to generates the frequency modulation (FM) signal. The magnitude of the quadrature voltage waveform is equal during adjusting the generated frequency. A Pspice simulation and experiment are done to verify the performance of the proposed circuit. The macro models of available ICs, LM13700 and AD830 are employed for simulation. The simulation and experimental results confirm theory well as expected.
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Design of High Input Impedance Voltage-mode Multifunction Biquad Filter with Independent Control of Natural Frequency and Quality Factor
(2020-06-01)
Jardrit, Peerapat
;
Jaikla, Winai
;
Siripogdee, Surapong
;
Chaichana, Amornchai
;
Sotner, Roman
The voltage differencing differential input buffered amplifier (VD-DIBA) is interesting active building block for voltage-mode (VM) circuit design due to its advantage features such as electronic tuning, high impedance at input voltage ports and low impedance at output voltage port etc. In this paper, the realization of two-inputs three-outputs voltage-mode filter using VD-DIBAs is presented in this paper. The filter employs two VD-DIBAs, two resistors and two capacitors connected to ground. Four filtering responses, band-pass (BP) VM function, highpass (HP) VM function, low-pass (LP) VM function, and band-reject (BR) VM function are obtained. Two input nodes for applying input voltage signal are high impedance. The presented biquad filter employs two active devices but the quality factor (Q) is tuned without disturbing the natural frequency (ω0). Also, the natural frequency tuning is linearly and electronically done through bias current. The proposed filter is designed and simulated using VD-DIBA constructed from commercially available ICs, LM3700 and AD830. The Pspice simulation results justify the good functionality of the filtering performance.
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Electronically Controllable Colpitts Oscillator with Amplitude Controllability Using Commercially Available ICs
(2023-01-01)
Chaichana, Amornchai
;
Mhuenpong, Ketsirin
;
Sotner, Roman
;
Jaikla, Winai
This paper proposes a sinusoidal oscillator realized from the LC Colpitts circuit configuration. For this purpose, the commercially available IC, LT1228 is chosen as active element. The current amplifier and grounded inductance simulator with electronic controllable gain and inductance value are respectively used to drive the oscillation condition and the oscillation frequency. These sub-circuits replace the conventional bipolar transistor-based current amplifier and wire coil inductor. Significant features of the proposed Colpitts oscillator include electronic and independent adjustment of oscillation frequency and condition, amplitude controllability of the sinusoidal waveform, and the absence of a wire coil inductor. The proposed oscillator has been tested through an experimental setup using an off-the-shelf IC, LT1228, to verify the theoretical analysis.
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Synthesis of biquad filters using two VD-DIBAs with independent control of quality factor and natural frequency
(2021-04-01)
Jaikla, Winai
;
Siripongdee, Surapong
;
Khateb, Fabian
;
Sotner, Roman
;
Silapan, Phamorn
This contribution presents the procedure to synthesis the voltage-mode active biquad filters using the active elements, voltage differencing differential input buffered amplifier (VD-DIBA). Two filtering categories, single input four output (SIFO) configuration and three input three output (TITO) configuration are proposed. Both proposed filters consist of two VD-DIBAs, two grounded capacitors and two resistors. All input voltage nodes for both biquad filters exhibit high impedance. The proposed SIFO biquad filter simultaneously provide four filtering responses, low pass (LP), band pass (BP), high pass (HP) and band reject (BR) functions, while the proposed TITO filter provides five filtering responses (including all pass (AP) function). The natural frequency (ω<inf>0</inf>) is linearly and electronically tuned without affecting the quality factor (Q). Also, the Q adjusting can be done without affecting the ω<inf>0</inf>. By modifying the proposed TITO biquad filter, the current controlled sinusoidal oscillator is achieved. The frequency of the generated sinewave is linearly tuned without affecting the condition of oscillation. The performances of the proposed circuits are simulated by Cadence software and the Spectre simulator of the Analog Design Environment using CMOS VD-DIBA in 0.18 μm TSMC CMOS technology and laboratory experiment using VD-DIBA constructed from commercially available ICs.

Chaichana, Amornchai

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