• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.3
• /
• pp.565-570
• /
• 2012

This paper has proposed a multi-channel low pass filter (LPF) for LTE-Advanced systems. The proposed LPF is an active-RC 5th chebyshev topology with three cut-off frequencies of 5 MHz, 10 MHz, and 40 MHz. A 3-bit tuning circuit has been adopted to prevent variations of each cut-off frequency from process, voltage, and temperature (PVT). To achieve a high cut-off frequency of 40 MHz, an operational amplifier used in the proposed filter has employed a PMOS cross-connection load with a negative impedance. A proposed filter has been implemented in a 0.13-${\mu}m$ CMOS technology and consumes 20.2 mW with a 1.2 V supply voltage.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1972-1974
• /
• 2004

This paper describes the high pass filter with notch charecteristics. The proposed circuits configuration consists of two uniformly distributed RC line (herein after is called URC) and two gain amplifiers ($K_1$ and $K_2$). With the appropriate $K_1$ and $K_2$ , the circuit has a steeper slope of magnitude response at pass band steeper than using a single gain amplifier.

• Journal of Sensor Science and Technology
• /
• v.29 no.4
• /
• pp.243-248
• /
• 2020

In this study, we applied transition-frequency modulation to prevent the flickering of light-emitting diodes (LEDs) in visible light communication (VLC). In the VLC transmitter, rectangular waveforms with transition frequencies of four and two in each bit time were used for the high and low bits, respectively, in the non-return-to-zero data. In the VLC receiver, an RC-high-pass filter (HPF) was used to eliminate the interference of the 120 Hz noise light from the adjacent lighting lamps, and an SR-latch circuit was used to recover the transmitted signal using spikes from the output of the RC-HPF. This configuration is useful for constructing VLC systems that are flicker-free and resistant to adjacent noise light interference.

• Journal of Sensor Science and Technology
• /
• v.27 no.3
• /
• pp.143-149
• /
• 2018

In this paper, we introduce an edge-spike modulation method for visible light communication (VLC). This method is effective in preventing LED flicker and 120 Hz noise interference in base-band VLC. In the VLC transmitter, edge-spikes are generated by passing the digital data through a simple RC-high pass filter (HPF). The LED modulation of the edge-spikes does not change the average power of the LED light; thus it prevents LED flicker. In the VLC receiver, the 120 Hz noise from other lighting lamps is easily eliminated by RC-HPF, while the edge-spike signal is detected normally. In our experiment, the message of an air-quality sensor was successfully transmitted using edge-spike modulation. This structure is useful in constructing, e.g., wireless gas monitoring sensor systems to warn and prevent harmful gas leakage accidents in buildings using LED light.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.10 no.4
• /
• pp.282-291
• /
• 2010

This paper presents a full-CMOS transmitter and receiver for VDSL2 systems. The transmitter part consists of the low-pass filter, programmable gain amplifier (PGA) and 14-bit DAC. The receiver part consists of the low-pass filter, variable gain amplifier (VGA), and 13-bit ADC. The low pass filter and PGA are designed to support the variable data rate. The RC bank sharing architecture for the low pass filter has reduced the chip size significantly. And, the 80 Msps, high resolution DAC and ADC are integrated to guarantee the SNR. Also, the transmitter and receiver are designed to have a wide dynamic range and gain control range because the signal from the VDSL2 line is variable depending on the distance. The chip is implemented in 0.25 ${\mu}m$ CMOS technology and the die area is 5 mm $\times$ 5 mm. The spurious free dynamic range (SFDR) and SNR of the transmitter and receiver are 67.5 dB and 41 dB, respectively. The power consumption of the transmitter and receiver are 160 mW and 250 mW from the supply voltage of 2.5 V, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.13 no.4
• /
• pp.322-331
• /
• 1988

In this thesis, an active RC filter using high order inverse chebyshev function is designed and the design method for cascading blocks with low sensitivity and maximum dynamic range is discussed. To have maximum dynamic range, we have proposed the simple algorithm with a pole-zero pairing, the cascading sequence by flatness matrix and optimum gain distribution for a given transfer function. And 2nd order Block is designed with negative feedback to improve the sensitivity problem which had a defect at active RC circuits. Using the suggested method, we have designed the active RC low pass filter of the normalized 7th order inverse chebyshev function, as a results, we have shown that this accord with the given specification.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.80.3-80
• /
• 2002

$\textbullet$ Janchitrapongvej Kanok(KMITL), $\textbullet$ Tangtisanon Prakit( KMITL), $\textbullet$ Janin Chainarong(KMITL), $\textbullet$ Panyanouvong Nouanchanh(KMITL), $\textbullet$ Saetia Sorapong(KMITL)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.396-397
• /
• 2011

This paper has proposed a multi-channel low pass filter (LPF) for LTE-Advanced systems. The proposed LPF is an active-RC 5th chebyshev topology with three cut-off frequencies of 5 MHz, 10 MHz, and 40 MHz. A 3-bit tuning circuit has been adopted to prevent variations of each cut-off frequency from process, voltage, and temperature (PVT). To achieve a high cut-off frequency of 40 MHz, an operational amplifier used in the proposed filter has employed a PMOS cross-connection load with a negative impedance. A proposed filter has been implemented in a $0.13-{\mu}m$ CMOS technology and consumes 20.2 mW with a 1.2V supply voltage.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.18 no.2
• /
• pp.14-21
• /
• 1981

This paper describes a method for realizing RC active filters, by the use of the CGIC's In realizing the CGIC circuit, every element in the circuit is selected so as to minimize the effect of the non -ideal characteristic of operational amplifers, and an extra element is added to the, CGIC circuit to compensate the parasitic capacitances of the circuit. The CGIC s are utilized in the design of active filters using ladder embedding technique. The design procedure is presented in detail and the application is illustrated by the design of a band-pass filter of high order.

• Journal of Power Electronics
• /
• v.18 no.6
• /
• pp.1670-1682
• /
• 2018

The further improvement of submarine propulsion is associated with the modularity of accumulator-fed inverters, such as cascaded inverters (CIs). CI technology guarantees smooth output voltages with reduced switch frequencies under linear loads. However, the output voltages of CIs are distorted under rectifier loads. This distortion requires harmonic suppression technology. One such technology is the repetitive controller (RC), which is commonly applied but suffers from poor performance in propulsion systems. In this study, the FFT spectrum of a CI under rectifier load is analyzed, and the harmonic contents are uneven in magnitude. For the purpose of harmonic suppression, the control gains at each harmonic frequency should be seriously considered. A RC with a specific harmonic gain compensation (SHGC) for CIs is proposed. This method provides additional control gains at low-order harmonic frequencies, which are difficult to achieve with conventional RCs. This SHGC consists of a band-pass filter (BPF) and proportional element and is easy to implement. These features make the proposed method suitable for submarine propulsion. Experimental results verify the feasibility of the improved RC.