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 - 10 of 24

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Synthesis of electronically tunable multifunction biquad filter using voltage differencing differential input buffered amplifiers
(2025-02-01)
Bunrueangsak, Sirigul
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Jaikla, Winai
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Chaichana, Amornchai
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Supavarasuwat, Piya
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Siripongdee, Surapong
Biquad filters are commonly used in analog circuits for various purposes in signal processing and communication applications. We synthesize an analog active biquad filter with five types of voltage-mode filtering functions. The filter is synthesized using a parallel passive resistor-inductor-capacitor (RLC) network and unity-gain voltage differencing amplifier. A voltage differencing differential input buffered amplifier (VD-DIBA) is the main active component, and the biquad filter has a three-input single-output (TISO) topology. By replacing the passive inductor and resistor with VD-DIBA-based inductance and resistance simulators with a subtractor, the TISO voltage-mode versatile filter is obtained from two VD-DIBAs, one resistor, and two capacitors connected to the ground. The proposed filter can provide five types of voltage-mode filtering functions: inverting bandpass and lowpass responses as well as noninverting band-stop, high-pass, and all-pass responses. The all-pass filter requires no additional active components. The three input voltage nodes have high impedance, and a low-impedance output voltage node facilitates cascade connections without using additional voltage buffers. In addition, the natural frequency and quality factor can be electronically tuned. The quality factor is controlled without disturbing the passband gain and natural frequency. The proposed filter is simulated and verified experimentally in the Personal Simulation Program with Integrated Circuit Emphasis (PSPICE) and through laboratory tests employing VD-DIBAs implemented using commercially available components.
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Single Active Element Based Electronically Controllable Capacitance Multiplier
(2022-07-15)
Jaikla, Winai
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Huaihongthong, Pintira
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Siripongdee, Surapong
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Chaichana, Amornchai
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Suwanjan, Peerawut
The realization of capacitance multiplier using the versatile active building block, namely voltage differencing differential difference amplifier (VDDDA) is presented in this paper. The realized capacitance multiplier is very simple consisting of one VDDDA, one MOS resistor (RM) and one grounded capacitor which is attractive for integration. The multiplication factor (KC) of the realized circuit can be electronically controlled via the bias current (IB) and control voltage (VC) without the need of any matching condition of active and passive element. Moreover, the multiplication factor can be adjusted to be more or less than one. The performances of the presented capacitance multiplier are verified through Pspice simulation using CMOS VDDDA in 0.18μm TSMC technology with ±0.9V power supplies. The multiplication factor is designed to be KC=2 by choosing VC=0.85V, IB=50μA and C=30 pF. The simulated multiplication factor is around 1.98. The simulated operational frequency range is around three decades (6.16 kHz-8.91MHz). The performances of the proposed circuit are also verified by the experiment using VDDDA implemented from the commercial ICs, AD830 and LM13700 with ±5V power supplies. The experiment is conducted under the same multiplication factor (KC=2) as the simulation by choosing RM=0.27 kω (1% passive resistor), IB=96.2μA and C=1nF. The experimental multiplication factor is around 2.06. The experimental operational frequency range is around three decades (1kHz-1.25MHz). By adjusting the bias current from 17.67μA to 400 μA, the experimental multiplication factor is controllable from 11.47 to 0.48. The percent deviation of the theoretical and experimental multiplication factor is lower than 5% when the value of bias current is greater than 39μA. These deviations stem from the effect of the parasitic capacitance and resistance in VDDDA. Moreover, the application example of the presented capacitance multiplier as the sinusoidal oscillator is presented. The performances of the presented oscillator verified via the experiment are well consistent with theoretical anticipation.
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A study of health service accessibility in aging society and technological development: A case of the urban community surround sirinthorn Hospital, Bangkok
(2020-11-04)
Thipayasothorn, Pastraporn
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Phetsinchorn, Aueamaumporn
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Chaichana, Amornchai
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Ruangrit, Thipawan
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Munkong, Pratum
The situation of health in aging society and the issues on travelling in city communities in Bangkok have a relationship with its environment where is under an investigation of health activities and patterns of travelling among the elderly. This research aims to examine health activities, patterns of travelling and factors influencing health service assess in city communities among the elderly. Following the objectives of the present study, suggestions for further development are given to relevant departments.The major findings of the situation on travelling and problems on receiving health service of the elderly who have lived in city communities of Sirindhorn hospital, Bangkok leads to some recommendations for developing patterns of travelling for health service, designing activities for the elderly with different ages to have appropriate health service and promoting an engaging environment in the communities
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Electronically and orthogonally tunable sito voltage-mode multifunction biquad filter using lt1228s
(2021-10-27)
Wai, May Phu Pwint
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Suwanjan, Peerawut
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Jaikla, Winai
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Chaichana, Amornchai
The commercially available IC LT1228 is an interesting active device due to its advantage features, such as a fast transconductance amplifier, a wide bandwidth over a wide range of voltage gain, low total harmonic distortion (THD), high impedance differential input, etc. The single-input triple-output (SITO) voltage-mode (VM) multifunction biquadratic filters using ICs, LT1228s are introduced in this research. This circuit design provides the three-filtering functions, low-pass (LP), high-pass (HP), and band-pass (BP), without changing the circuit architecture. It comprises three LT1228s, four resistors, and two capacitors connected to the ground. The low impedance voltage output nodes are HP and BP responses. The quality factor (Q) and the pole frequency (ω0) can be electronically and orthogonally tuned by altering the third LT1228's bias current (IB). The PSPICE simulation and the experiment are verified to describe the circuit operation.
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Classroom Management as Virtual World for Creating Professional Teaching Environment
(2024-01-01)
Thipayasothorn, Pastraporn
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Chaichana, Amornchai
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Phetsinchorn, Aueamaumporn
Research and innovation for community or local development, aims at providing the individuals with a high quality of life and enhancing capabilities for competition through collaborative efforts of stakeholders, including beneficiaries in the area, especially the academic sector of which powerful educational institutions in the central and metropolitan areas of Thailand. Innovation in vocational education management through online teaching environments intends to have educational innovations in the central and metropolitan areas as a mechanism and process of educational reform that can manage online teaching in line with the local context. This involves flexible and adaptable management that eliminates the need for travel and reduces consumption of resources. This is achieved by research objective of 1) developing innovations in vocational education management through online teaching environments to enhance educational efficiency, 2) reducing educational quality disparities by designing virtual reality training centers for professional skill development, with a case study in the field of art and design, and 3) developing mechanisms for collaborative education management in the community, through the design and use of application programs to create a professional teaching environment. Therefore, this research and innovation in vocational education management in the central region of Thailand through online teaching environments can enhance self-directed learning. This involves designing and developing learning technology, creating a virtual world to establish a professional teaching environment, and innovating learning application programs from 400 sampling. The education system in this changing crisis has a responsibility to stimulate and revive the grassroots economy after the crisis. This emphasizes the crucial role of education as a continuous tool in building economic and social resilience later.
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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
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Buakhong, Unchittha
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Siripongdee, Surapong
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Khateb, Fabian
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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
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Jaikla, Winai
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Siripongdee, Surapong
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Sotner, Roman
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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
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Adhan, Suchin
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Chaichana, Amornchai
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Sotner, Roman
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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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Electronically Tunable TISO Voltage-Mode Universal Filter Using Two LT1228s
(2022-01-01)
Wai, May Phu Pwint
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Jaikla, Winai
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Siripongdee, Surapong
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Chaichana, Amornchai
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Suwanjan, Peerawut
This study aims to design an electronically tunable voltage-mode (VM) universal filter utilizing commercially available LT1228 integrated circuits (ICs) with three-input and single-output (TISO) configuration. With the procedure based on two integrator loop filtering structures, the proposed filter consists of two LT1228s, four resistors, and two grounded capacitors. It realizes five filter output responses: low-pass, all-pass, band-reject, band-pass, and high-pass functions. By selecting input voltage signals, each output responses can be achieved without changing the circuit architecture. The natural angular frequency can be controlled electronically. The input voltage nodes Vin1 and Vin3 possess high impedance. The output node has low impedance, so it can be cascaded to other circuits. The performance of the proposed filter is corroborated by PSpice simulation and hardware implementation which support the theoretical assumptions. The result shows that the range of total harmonic distortion (THD) is lower than 1%, and that the higher the temperature is, the lower the natural angular frequency is.
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Development of mobile application program to promote travel for the elderly in the city community to use healthcare services in Sirindhorn Hospital, Bangkok
(2022-04-01)
Thipayasothorn, Pastraporn
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Chaichana, Amonchai
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Phetsinchorn, Aueamaumporn
;
Ruangrit, Thipawan
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Munkong, Pratum
Aging health circumstances combined with travel challenges in the city community of Sirinhorn hospital have a direct relation to the deteriorating health and environment of the elderly, which are generally based on a number of different old age-related diseases. Hence, this is the main reason for healthcare service provision to the elderly for enhanced life quality. In addition, a number of other broader factors such as the overall service system of hospitals, hospital accessibility, public transportation system, the elderly’s private vehicles, and supportive technology for the elderly’s travel to hospital can potentially impact their means to acquire hospital-based health services. Therefore, this two-fold research was conducted to develop a mobile application program to promote travel for the elderly in the city community, who currently seek health services at Sirindhorn hospital in Bangkok and to evaluate the developed mobile application program’s effectiveness and efficiency in supporting the elderly’s travel to hospital. The program development process involved specialists, experts and thirty elderly participants who pilot-tested the developed mobile application program for their travels to the hospital. Results showed that participants were satisfied with their experiences in using the developed application program, particularly through the convenience in giving and acquiring information on the application program that significantly supported their travels to the hospital. This study presented implications for public healthcare stakeholders in their provision of effective health services to the Thai elderly.

Chaichana, Amornchai

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