• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.3
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• pp.285-285
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• 1999

This paper describes a Frequency Shift Keying (FSK) modulator and demodulator and the experimented underwater data ommunication equipment to transfer the analog echo signal in real-time from an underwater vehicle to the mother ship. The system consists of an echo signal transfer unit equipped to the vehicle and an ultrasonic receiver equipped on the ship. The former includes an ultrasonic transceiver unit of 180kHz for echo detection and a continuous wave transmitter of 50kHz with a FSK modulator for echo transmission to the ship. The latter includes an ultrasonic receiver of 50kHz and the FSK demodulator. The results of experiment are as follows. 1. The characteristics of the FSK modulating and demodulating circuits designed with the use of C-MOS IC 4046 was good and confirmed its usefulness in underwater data communication system.2. The prototype ultrasonic transceiver unit shows profitable driving power while the pulse duration was short less than 3 msec, but it was found that the driving power is not sufficient while the long pulse duration or continuous wave is used. The gain of the ultrasonic receiver was 80 dB and the receiving bandwidth 700Hz (at - 3 dB point).3. It was found that the system designed by the author has some possibility to use in underwater echo transfer.4. At the FSK modulator, the widths of voltage and frequency which represent linearity were 3.5 V, 1600Hz, respectively, at the FSK demodulator 2.6 V, 700Hz, respectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.15-20
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• 2013

In narrowband communication systems operating in VHF and UHF bands, the performance degradation due to a frequency offset is inevitable. In this paper, we propose a frequency offset reduction scheme using the dual-band FSK modulation for narrowband communications. The proposed scheme not only offer a relatively reliable performance under a severe frequency offsets, but also can obtain a frequency diversity gain in Rayleigh fading channel.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1134-1136
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• 2002

This paper proposes a FSK(Frequency Shift Keying) transmitter which has a inverter for power amplification instead of linear amplifier. As it can generate large signal using resonant circuit under the low voltage source even if the impedance of antenna is large as like a loop antenna of TWC(Train to Way-side Communication) system. In this paper, the proposed fully digital controlled transmitter including FSK modulation is presented and its control schemes are discussed.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.967-970
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• 2014

An efficient peak detection algorithm in magnitude spectrum is proposed to distinguish the M-frequency shift keying(FSK) signals from other digitally modulated signal. In addition, recognition of the modulation order estimation of FSK signals is also studied based on the fact that the magnitude spectrum of FSK signals reveals the number of peaks equal to the modulation order. When no a priori information about the signals, we utilize the histogram of the magnitude spectrum to determine the threshold which is important factor in peak detection algorithm. The simulation results show high probability of classification under 500 symbols and signal-to-noise ratio(SNR) higher than 4dB.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.805-809
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• 2006

To secure resources, submarine environment should be firstly explored. On that occasion, the withdrawal of the instrument is important and the submarine ultrasonic wave should be stably identified regardless submarine environment and passive factor. In the existing control methods, the control informations, received from an observation instrument, are identified used by hardware and repeatedly compared with standard information. Hereupon, a marine observation instrument remote control system using the combination of FSK and ASK that was improved its controllability and movability was presented in this paper. Likewise, the logicality of communication algorithm were ascertained by experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1805-1811
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• 2005

We analyzed of the receiver which received OOK and the FSK transmission signal that were a general digital transmission technique in a WDM system. We expressed various error probability with the m which was bandwidth and a bit numerical function and carried out performance evaluation of a receiver in a performance evaluation way. When error probability was $10^{-4}$ which is m=10, as for the receive sensitivity of OOK, the $1.7{\times}10^2$, FSK got $2.2{\times}10^2$ through simulation. And the receive sensitivity of OOK and FSK was able to get each $2.15{\times}10^2$ and $3.07{\times}10^2$ when it was error probability of $10^{-9}$ which is m = 25. Transmission of 23Gb/S showed that it was possible when we does the $10^{-9}$ that was basis error probability of a light communication system with a basis through this, and a coding profit was with for and transmission capacity of 75Gb/s confirmed that it was possible if a code rate was with 0.8.

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.408-414
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• 2007

Research advances in the areas of micro-sensor device and wireless network technology, has made it possible to develop energy efficient and low cost wireless sensor nodes. In this paper, the forward error control (FEC) scheme for lower power consumption and excellent BER(Bit Error Rate) performance during transmission propose in multi-hop wireless sensor network based on FSK modem. The FEC technique uses extra processing power related to encoding and decoding, it is need complex functions to be built into the sensor node. The probability of receiving a correct bit and codeword for relaying a frame over h nodes to the sink node is calculated as a function of channel parameter, number of hops, number of bits transmitted and the distance between the different nodes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.83-91
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• 2008

To design the light control system using the PLC(Power Line Communication) with the ballasts of MH(Metal Halide) lamps, we analyzed the noise effect on the power line by the electronic ballast. For the power line characteristics are changed by the loads, the ballast have to be designed to be suitable to the PLC. Therefore, this paper proposed the optimal ballast and designed two kinds of PLM(Power Line Modem) which one is ASK type and the other is FSK type. Two type of PLM have used the manchester codes or DS/SS code. Experimental results have shown that the FSK type modem by the DS/SS coding technique have the best characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.194-200
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• 2003

In this paper, FSK(Frequency Shift Keying) demodulator which is widely used for FH-SS system is designed and the experimental results are analyzed. The performance of the ADPLL(All-digital Phase-Locked-Loop), which is the main part of the demodulator circuit, is analyzed by the computer program. Using Maxplus-II tool provided by altera. co., ltd, each part of the ADPLL is designed and all of them is integrated into EPM7064SLC44-10 chip. And the simulation results are compared with the characteristics of the implemented circuits for analysis. There is about 2${\mu}\textrm{s}$ difference in time constant of the PLL. This difference is not critical in the demodulator. And the experimental results show that the transmitted data is well demodulated when the phase difference between the FSK modulated signal and the reference signal is about 180 degree.

• The Journal of the Acoustical Society of Korea
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• v.40 no.3
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• pp.219-227
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• 2021

This paper proposed an Orthogonal Frequency Division Multiplexing (OFDM) based biomimetic communication method using a dolphin whistle which covertly transmits communication signals to allies. The proposed method divides the dolphin whistle into several time slots corresponding to a number of OFDM symbols, and modulates the communication signal by mapping differential phase shift keying (DPSK) symbols into subcarriers that have the frequency bands of the dolphin whistle in each slot. The advantages of the proposed method are as follows: In the conventional Chirp Spread Spectrum (CSS) and Frequency Shift Keying (FSK) based biomimetic communication methods, the discontinuity of the frequency contour is large, but the proposed method can reduce the discontinuity. Even if the modulation order is increased, the degradation of the mimicking performance is small. The computer simulations demonstrate that the Bit Error Rate (BER) and mimicking performance of the proposed method are better performance than those of the conventional CSS and FSK.