• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.30B no.5
• /
• pp.73-81
• /
• 1993

We have developed a system which can analyze the status of signal sent from/received to a signalling service equipment within the fully electronic switching system such as TDX-10. The system has such functions that acquire PCM signal of the preferred channel from the subhighway of the thirth-two channel by which a Universal Signal Tr ansceiver Unit(USTU) is connected with Time Switch Unit (TSU), and then classify the type of signal such as R2MFC/DTMF/CCT/VOICE, and determine the digit. Up to now, we have analyzed the frequency spec trum using the FFT. This paper describes the developement of PCM acquirer which can analyze the signal characteristics by acquiring the PCM signal in SHW(subhighway), and proposes the CZT(Chirp Z-Transform) algorithm. An algorithm which analyzes the acquired signal and determines the signal frequency and the corresponding power spectrum using the CZT is also discussed here.

• Proceedings of the IEEK Conference
• /
• 2000.07a
• /
• pp.84-87
• /
• 2000

The system has a function of acquirement PCM signal of the preferred channel from the subhighway (SHW), connecting a universal signal transceiver unit and time switch unit, and then it classifies the type of signal such as R2MFC/ DTMF/ CCT/ VOICE, and finally discriminates the digit. This paper describes the spectral analysis of the PCM acquisition system usng the quick Fourier transform(QFT), and discusses the algorithm of signal analysis and discrimination.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.4
• /
• pp.26-33
• /
• 2010

This paper presents a multi-channel capacitive touch sensing unit for SoC applications. This unit includes a simple common processing unit and switch array to detect the touch sensing input by capacitive-time(C-T) conversion method. This touch sensor ASIC is designed based on the Capacitive-Time(C-T) conversion method to have advantages of small current and chip area, and the minimum resolution of the unit is 41 fF per count with the built-in sensing oscillator, LDO regulator and $I^2C$ for no additional external components. This unit is implemented in 0.18 um CMOS process with dual supply voltage of 1.8 V and 3.3 V. The total power consumption of the unit is 60 uA and the area is 0.26 $mm^2$.

• Proceedings of the KSRS Conference
• /
• 2005.10a
• /
• pp.493-496
• /
• 2005

The PMU (Payload Management Unit) in MSC (Multi-Spectral Camera) is the main subsystem for the management, control and power supply of the MSC payload operation. The PMU shall handle the communication with the BUS (Spacecraft) OBC (On Board Computer) for the command, the telemetry and the communications with the various MSC units. The PMU will perform that distributes power to the various MSC units, collects the telemetry reports from MSC units, performs thermal control of the EOS (Electro-Optical Subsystem), performs the NUC (Non-Uniformity Correction) function of the raw imagery data, and rearranges the pixel data and output it to the DCSU (Data Compression and Storage Unit). The BUS provides high voltage to the MSC. The PMU is connected to primary and redundant BUS power and distributes the high unregulated primary voltages for all MSC sub-units. The PSM (Power Supply Module) is an assembly in the PMU implements the interface between several channels on the input. The bus switches are used to prevent a single point system failure. Such a failure could need the PSS (Power Supply System) requirement to combine the two PSM boards' bus outputs in a wired-OR configuration. In such a configuration if one of the boards' output gets shorted to ground then the entire bus could fail thereby causing the entire MSC to fail. To prevent such a short from pulling down the system, the switch could be opened and disconnect the short from the bus. This switch operation is controlled by the BUS.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.9
• /
• pp.685-691
• /
• 2003

This work describes a 3 V 12b 100 MS/s CMOS digital-to-analog converter (DAC) for high-speed communication system applications. The proposed DAC is composed of a unit current-cell matrix for 8 MSBs and a binary-weighted array for 4 LSBs, considering linearity, power consumption, chip area, and glitch energy. The low-glitch switch driving circuit is employed to improve the linearity and the dynamic performance. Current sources of the DAC are laid out separately from the current-cell switch matrix core. The prototype DAC is implemented in a 0.35 urn n-well single-poly quad-metal CMOS technology. The measured DNL and INL of the prototype DAC are within $\pm$0.75 LSB and $\pm$1.73 LSB, respectively, and the spurious-free dynamic range (SFDR) is 64 dB at 100 MS/s with a 10 MHz input sinewave. The DAC dissipates 91 mW at 3 V and occupies the active die area of 2.2 mm ${\times}$ 2.0 mm.

• Journal of IKEEE
• /
• v.19 no.3
• /
• pp.304-310
• /
• 2015

A SCALDO(Supercapacitor Assisted LDO) regulator is a new regulator having advantages of a SMPS(Switch Mode Power Supply) which has a good efficiency and a LDO(Low Drop-out) regulator which has stable output characteristics and good EMI(Electro Magnetic Interference) characteristics. However, a conventional SCALDO regulator needs a lot of power consumption to control its switches and it drops an efficiency of the circuit. In this paper, to reduce switching power consumption and improve an efficiency of the circuit, a new SCALDO regulator adopting MOSFETs as its switching parts is proposed and it is found out that the proposed SCALDO regulator has the maximum 9.5% higher efficiency than the conventional SCALDO regulator. We also try to simplify production process of the circuit by changing switching control method of the circuit from MCU(Micro-controller unit) based firmware control to hardware control using a comparator and a T-F/F(Flip Flop).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.12
• /
• pp.1678-1687
• /
• 2013

This paper describes a prototype of 3-phase 3.3kV/220V 6kVA modular semiconductor transformer developed in the lab for feasibility study. The developed prototype is composed of three single-phase units coupled in Y-connection. Each single-phase unit with a rating of 1.9kV/127V 2kVA consists of a high-voltage high-frequency resonant AC-DC converter, a low-voltage hybrid-switching DC-DC converter, and a low-voltage hybrid-switching DC-AC converter. Also each single-phase unit has two DSP controllers to control converter operation and to acquire monitoring data. Monitoring system was developed based on LabView by using CAN communication link between the DSP controller and PC. Through various experimental analyses it was verified that the prototype operates with proper performance under normal and sag condition. The system efficiency can be improved by adopting optimal design and replacing the IGBT switch with the SiC MOSFET switch. The developed prototype confirms a possibility to build a commercial high-voltage high-power semiconductor transformer by increasing the number of series-connected converter modules in high-voltage side and improving the performance of switching element.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.5
• /
• pp.461-466
• /
• 2012

This paper describes the development and test result of X-band Transmitter flight model(FM) of STSAT-3 by satellite research center(SaTReC), KAIST. The communication sub-system of STSAT-3 is consist of two different frequency band channels. S-band frequency is used for Telemetry & Command, and X-band frequency is used for mission data. Payload observations data in Mass Memory Unit (MMU) is modulated by QPSK modulator in X-band Transmitter, and then QPSK modulation signal is transmitted to antenna through transfer switch. In this Paper, we described the results of modulation, low-pass filter design, power amp development, and switch test. The FM XTU is delivered Spacecraft Assembly, Integration and Test(AIT) level through the completion of functional Test and environmental(vibration, thermal vacuum) Test successfully.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.3 no.4
• /
• pp.211-216
• /
• 2003

This work describes a 3 V 12b 100 MS/s CMOS digital-to-analog converter (DAC) for high-speed communication system applications. The proposed DAC is composed of a unit current-cell matrix for 8 MSBs and a binary-weighted array for 4 LSBs, trading-off linearity, power consumption, chip area, and glitch energy with this process. The low-glitch switch driving circuits are employed to improve linearity and dynamic performance. Current sources of the DAC are laid out separately from the current-cell switch matrix core block to reduce transient noise coupling. The prototype DAC is implemented in a 0.35 um n-well single-poly quad-metal CMOS technology and the measured DNL and INL are within ${\pm}0.75$ LSB and ${\pm}1.73$ LSB at 12b, respectively. The spurious-free dynamic range (SFDR) is 64 dB at 100 MS/s with a 10 MHz input sinewave. The DAC dissipates 91 mW at 3 V and occupies the active die area of $2.2{\;}mm{\;}{\times}{\;}2.0{\;}mm$

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.6
• /
• pp.284-292
• /
• 2005

Because all of the short-circuit testing laboratories have the limitation of test facilities, the synthetic making test methods have been used to estimate the short-circuit making performance of the ultra high-voltage circuit breaker as the alternative to direct test methods. So, KERI(Korea Eelctrotechnology Research institute) has completed the construction of the synthetic making test facilities using the low capacity step-up transformer method which fulfill the requirements specified in newly revised IEC 62271-100 Edition 1.1(2003) and have the testing capability up to 550kV, 63kA full-pole circuit breaker. The test facilities using the low capacity step-up transformer method presented in this paper are made up of the unit equipments such as HCS(High-speed Closing Switch), ITMC(Initial Transient Making Current) circuit and UP TR(low capacity step-up transformer) and have the operating range of 17.6$^{\circ}$ $\~$ 145.1$^{\circ}$ for testing the circuit breaker rated on up to 50kA and 43.1$^{\circ}$ $\~$ 119.6$^{\circ}$ for more than 50kA.