• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.329-334
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• 2009

When an optical disc is being played. the pick-up converts light to analog signal at first. The analog signal is equalized for removing the inter-symbol interference and then the equalized analog signal is converted into the digital signal for extracting the synchronized data and clock signals. There are a lot of algorithms that minimize the BER in extracting the synchronized data and clock when high. density optical disc like BD is being played in low speed. But if the high-density optical disc is played in high speed, it is difficult to adopt the same extraction algorithm to data PLL and PRML architecture used in low speed application. It is because the signal with more than 800MHz should be processed in those architectures. Generally, in the 0.13-${\mu}m$ CMOS technology, it is necessary to have the high speed analog cores and lots of efforts to layout. In this paper, the parallel data PLL and PRML architecture, which enable to process in BD 8x speed of the maximum speed of the high-density optical disc as the extracting data and clock circuit, is proposed. Test results show that the proposed architecture is well operated without processing error at BD 8x speed.

• Transactions on Semiconductor Engineering
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• v.2 no.3
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• pp.1-5
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• 2024

This paper presents a crystal-less reference clock recovery (CR) frequency synthesizer with compensation designed for Bluetooth Low Energy (BLE) Smart-tag applications, operating at frequencies of 32, 72, and 80MHz. In contrast to conventional frequency synthesizers, the proposed design eliminates the need for external components. Using a single-ended antenna to receive a minimal input power of -36dBm at a 2.4GHz signal, the CR synthesizes frequencies by processing the RF signal received through a Low Noise Amplifier ( L N A ) . This approach allows the system to generate a reference clock without relying on a crystal. The received signal is amplified by the LNA and then input to a 16-bit ACC (Automatic Clock Compensation) circuit. The ACC compares the frequency of the received signal with the oscillator output signal, using the synthesis of a 32MHz reference clock through a frequency compensation method. The oscillator is constructed using a Ring Oscillator (RO) with a Frequency Divider, offering three different frequencies (32/72/80MHz) for various system components. The proposed frequency synthesizer is implemented using a 55-nm CMOS process.

• Nuclear Engineering and Technology
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• v.24 no.2
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• pp.168-177
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• 1992

The importance of the study of two phase flow phenomena has increased for both fuel performance and safety analysis of nuclear power plants. In the analysis of two phase flow system, an accurate prediction of local void fractions is very important. In this study, a vertical rectangular subchannel having 4 electrically heated rods is constructed for the measurement of local void fraction under two phase flow. The measurement has been conducted by electrical conductivity probes and signal processing circuit which are known to be adequate to measuring local void fraction. Also experiments are performed with varying the inlet flow rate to search for radial void fraction profile accordingly to the different flow rate even with the same averaged void fraction. From the result of experiments, the validity of electrical conductivity probe and electrical circuit is confirmed.

• Journal of IKEEE
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• v.23 no.2
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• pp.580-585
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• 2019

Batteries are being used in ESS, electric vehicles and uninterruptible power backup systems. Lead-acid batteries are the most used batteries for high capacity power back up equipment due to their high reliability and low price advantages. It is very important to estimate the chargeable capacity(SoH), and many algorithms were proposed to estimate the internal resistance of the battery. In this paper, the Battery Monitoring System(BMS) for high capacity uninterruptible power supply for IDC is proposed. A simple algorithm for estimating internal resistance was proposed. An computational block diagram of the proposed signal processing algorithm and BMS system configuration of CPU and analog circuit were shown. The proposed method was proved useful by presenting data examples of application to actual IDC sites.

• Journal of Sensor Science and Technology
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• v.28 no.1
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• pp.1-6
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• 2019

This paper presents an air flow sensor (AFS) based on a polymer thin film. This AFS primarily consists of a polymer membrane attached to a metal-patterned glass substrate and a temperature-sensing element composed of NiCr. These two components were integrated on a single glass substrate. The AFS measures changes in capacitance caused by deformation of the polymer membrane based on the air flow and simultaneously detects the temperature of the surrounding environment. A readout integrated circuit (ROIC) was also fabricated for signal processing, and an ROIC chip, 1.8 mm by 1.9 mm in size, was packaged with an AFS in the form of a system-in-package module. The total size of the AFS is 1 by 1 cm, and the diameter and thickness of the circular-shaped polymer membrane are 4 mm and $15{\mu}m$, respectively. The rate of change of the capacitance is approximately 11.2% for air flows ranging between 0 and 40 m/s.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.112-119
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• 1996

Among the various type of accelerometer, the servo rebalancing type accelermoter can be suitable for Inertial Navigation System, because of its high sensitivity and good response in low frequency. In this paper, we proposed a new technology to control inductive tuype accelerometer utilizing digital PWM method. The new developed digital PWM control has special design scheme for transmitting measurement value to outer device in its servo ollp. So it has no quantized error of transforming outputs of sensors to digital domain. The quantized error may make serious problem in INS system, because outputs of sensor are integrated once or twice by digital computer and it happens every sensor reading times. Therefore, in order to get the accurate information such as displacement, it is necessary to measure accurately the input current. In addition, Digital Signal Processing needs digital data transmission, digital PWM method is adaptive for this purpose. We realized a practical circuit for digital PWM control, analyzed the stability of the circuit, and designed the controller etc. In this study, we solved many practical problem for this application, and got out good results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.827-830
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• 2011

In this paper, a wind speed & direction module and the DSP(Digital Signal Processor) sensor interface circuit board are proposed. This DSP system accepts and process the informations from a wind speed & direction module, the atmospheric pressure sensor, the ambient air temperature sensor and transfers it to the PC monitering system. Especially, a wind speed & direction module and a DSP hardware are directly designed and applied. A wind speed & direction module have a construction that it have four film type RTD(Resistive Temperature Detectors) or film type Piezo sensors adhered around the circular metal body for obtaining vector informations about wind. By this structure, the module is enabled precise measurement having a robustness about vibration, humidity, corrosion. A sensor signal processing circuit is using TMS320F2812 TI(Texas Instrument) Corporation high speed DSP.

• Journal of the Korea Society of Computer and Information
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• v.15 no.3
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• pp.11-18
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• 2010

In this study, the pulse of radial artery and oxygen saturation are detected using photoelectric plethysmograph method. Using our device designed reflection type, we can detect the reflected light by radial artery and by switching circuit, we can also separate to 625nm band signal and 940nm band signals. The separated signals are converted as a pulse data by the pulse signal processing circuit. In this study, the reflection type of oxygen saturation calculation method is applied instead of the transmission type because of the reflection type sensor is used to measure the radial artery. As a result, we can detect about 97% accuracy of the oxygen saturation compare with the conventional method. For the accurate signals, the wrist band with sensor was designed and fixed on the radial artery. As a result, this wrist band type sensor was applicable to prevent position errors from motion artifact and could increase the accuracy during the measuring.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.688-698
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• 2016

In this paper, we investigate the achievable sum rate and energy efficiency of downlink massive multiple-input multiple-output antenna systems with zero-forcing precoding, by taking into account the randomness of user locations. Specifically, we propose two types of non-uniform user distributions, namely, center-intensive user distribution and edge-intensive user distribution. Based on these user distributions, we derive novel tight lower and upper bounds on the average sum rate. In addition, the impact of user distributions on the optimal number of users maximizing the sum rate is characterized. Moreover, by adopting a realistic power consumption model which accounts for the transmit power, circuit power and signal processing power, the energy efficiency of the system is studied. In particular, closed-form solutions for the key system parameters, such as the number of antennas and the optimal transmit signal-to-noise ratio maximizing the energy efficiency, are obtained. The findings of the paper suggest that user distribution has a significant impact on the system performance: for instance, the highest average sum rate is achieved with the center-intensive user distribution, while the lowest average sum rate is obtained with the edge-intensive user distribution. Also, more users can be served with the center-intensive user distribution.

• Journal of the Korea Society of Computer and Information
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• v.3 no.2
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• pp.77-84
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• 1998

The continuous time signal system by development of CMOS technology have been receiving consideration attention. In this paper, Low pass filter using CMOS floating resistor have been designed with cut off frequency for speech signal processing. Especially a new floating resistor consisting entirely of CMOS devices in saturation has been developed. Linearity within $\pm$0.04% is achieved through nonlineartiy via current mirrors over an applied range of $\pm$1V. The frequency response exceeds 10MHz, and the resistors are expected to be useful in implementing integrated circuit active RC filters. The low pass filter designed using this method has simpler structure than switched capacitor filter. So reduce the chip area. The characteristics of the designed low pass filter using this method are simulated by pspice program.