• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권2호
• /
• pp.658-672
• /
• 2021

Since the signal with strong power need be demodulated first for successive interference cancellation (SIC) receiver in non-orthogonal multiple access (NOMA) systems, the base station (BS) need inform the near user terminal (UT), which has allocated higher power, of the far UT's modulation mode. To avoid unnecessary signaling overhead of control channel, a blind detection algorithm of NOMA signal modulation mode is designed in this paper. Taking the joint constellation density diagrams of NOMA signal as the detection features, the deep residual network is built for classification, so as to detect the modulation mode of NOMA signal. In view of the fact that the joint constellation diagrams are easily polluted by high intensity noise and lose their real distribution pattern, the wavelet denoising method is adopted to improve the quality of constellations. The simulation results represent that the proposed algorithm can achieve satisfactory detection accuracy in NOMA systems. In addition, the factors affecting the recognition performance are also verified and analyzed.

• 전기학회논문지
• /
• 제66권2호
• /
• pp.425-430
• /
• 2017

This paper presents a novel method for identification of FSK modulated radar signal. Three features which measure the number of frequency tones, the regularity of the frequency shifting, and the diversity of power spectrum of detected radar signal, are introduced. A Two-step combined maximum likelihood classifier was used to identify the details of the detected FSK signal; the modulation order and the use of Costas code. We attempted to divide FSK signal into binary FSK, ternary FSK, 8-ary FSK, and FSK with Costas code of length 7. The simulation results indicated that the proposed methods achieves an averaged identification accuracy was 99.93% at a signal-to-noise of 0 dB.

• 대한전자공학회논문지TC
• /
• 제40권10호
• /
• pp.103-109
• /
• 2003

기존의 Multiple-Subcarrier변조 방식에 4-차원(4-D)신호를 이용한 Optical Wireless통신 방식을 제안하였다. 4-D 신호는 신호파형 최적화 기술 (OSW, Optimization Technique of Signal Waveforms)을 이용하여 유도하고 Multiple-Subcarricr의 block coder에 적용함으로써 출력 신호점 간의 Euclidean distance를 최대화하였다. 그 결과 고정 dc 바이어스를 부가한 상태에서 시스템에서 요구되는 Normalized power를 QPSK에 비해 3 dB, Reserved Subcarrier 나 Minimum Power에 비해 최대 3.3 dB 를 각각 절감하였고 normalized bandwidth 1.125 ∼ 1.25의 범위에서 QPSK에 비해 평균 3 dB, Res. Subcarrier 방식에 비해 2 ∼ 4 dB, Min. Power 방식에 비해 0 ∼ 3 dB를 각각 절감하였다.

• 한국정보통신학회논문지
• /
• 제23권10호
• /
• pp.1275-1281
• /
• 2019

무선 신호의 자동 변조 인식은 지능형 수신기의 주요한 작업으로 다양한 민간 및 군대 응용분야가 있다. 본 논문에서는 딥 뉴럴 네트워크 모델을 기반한 무선통신에서 전파신호의 변조 방식을 식별하는 방법을 제안한다. 순차적인 데이터에 대해 장기적인 패턴을 잡아내는데 용이한 LSTM 모델을 통과하여 얻은 연속적인 신호의 특징값을 딥 뉴럴 네트워크의 입력 데이터로 사용하여 신호의 변조 패턴을 분류한다. 변조된 신호의 진폭 및 위상, 동상(In-phase) 반송파, 직각 위상(Quadrature-phase) 반송파의 값을 LSTM 모델의 입력 데이터로 사용하여 분류한다. 제안된 학습 방법의 성능을 검증하기 위해, 다양한 신호 대 잡음비로 10 가지 유형의 변조 신호를 포함하는 대형 데이터 세트를 사용하여 학습하고 테스트한다. 본 논문의 변조 인식 프로그램은 신호의 사전 정보가 없는 환경에서 변조방식을 예측하는데 적용될 수 있다.

• Journal of the Optical Society of Korea
• /
• 제16권4호
• /
• pp.401-408
• /
• 2012

The amplitude error of phase modulator used in closed-loop fiber optic gyroscope has occurred by the temperature dependency of the electro-optic coefficient, and also can be due to the square-wave dither signal which is generally applied for eliminating the deadzone. This error can cause bias drift and scale factor error. This paper analyzes the temperature dependency of the modulation amplitude and the relationship with the scale factor of the gyroscope, and deals with an amplitude control method. The error calculation logic considering the dither signal is implemented on the signal processing module. The result of experiments from a prototype gyroscope shows the effect of the modulation amplitude control and a considerable improvement on performances.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 B
• /
• pp.1129-1133
• /
• 2002

This paper presents an electronic ballast using a novel multiplex modulation method for the metal halide lamp. The proposed modulation method, which has a modulating signal of swept multiplex frequency, can eliminate the acoustic resonance more effectively than the conventional modulation method, which has a modulating signal of constant frequency. For the purpose of future application specific integrated circuits (ASIC), the controller of the proposed ballast has been designed only with erasable programmable logic devices (EPLDs), but without a microprocessor. In this paper, detailed proposed modulation schemes are described and experimental results on the proto-type 150W metal halide lamp ballast with the proposed modulation method are discussed.

• 대한전자공학회논문지
• /
• 제13권6호
• /
• pp.24-29
• /
• 1976

A study is presented on the DDM (double delta modulation) system which incorporates another modulation loop in front of the delta modulation system. DDM is proposed to delta modulate the error signal which is derivated through the ordinary delta modulation. This system is constructed simply by adding a differential amplifier and an integrator to the basic DM system. Since signal-to-quantization noise ratio SNR is the most informative measure of quantizer performance, the formula of the max. SNR of the DDM system is derived and investigated experimentally for a sinusoidal input. The max. SNR of the DDM is larger than that of DM in low bit rate region and vice versa in high bit rate region.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 D
• /
• pp.2597-2599
• /
• 2001

This paper has developed the power line interphone system with the amplitude modulation technique. We described the Amplitude modulation and demodulation circuit and the line coupler for the implementation of the power line interphone. and suggested the experimental result for the signal attenuation, demodulated signal, spectrum.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.252-255
• /
• 2004

This paper presents a new technique to generate the 1-bit signal by decoding Pulse Width Modulation (PWM) signal to a binary file before programming onto the ROM. Since each PWM signal requires only 1-bit digital signal, PWM signal and other forms of digital signal related to multi-bit can be simply generated. The results demonstrate that using this new technique to generate the PWM signal can simplify the process and hardware complication. Moreover, the signal's data and frequency can be easily modified by programming the data onto the ROM and using the counter, respectively, which can reduce the size of the circuit and make the PCB easier.

• International Journal of Internet, Broadcasting and Communication
• /
• 제11권3호
• /
• pp.27-33
• /
• 2019

Quadrature spatial modulation (QSM) utilizes the in-phase and quadrature spatial dimensions to transmit the real and imaginary parts, respectively, of a single signal symbol. Improved QSM (IQSM) builds upon QSM to increase the spectral efficiency by transmitting the real and imaginary parts of two signal symbols using antenna combinations of size of two. In this paper, we propose a double QSM (DQSM) scheme that transmits the real and imaginary parts of two signal symbols independently through any of the transmit antennas. The two signal symbols are drawn from two different constellations of the same size with the first symbol drawn from any of the conventional modulation sets while the second is drawn from an optimally rotated version of the first constellation. The optimum rotation angle is obtained through extensive Monte Carlo simulations to minimize the bit error rate (BER) of the system. Simulation results show that for a given spectral efficiency, DQSM performsrelatively close to IQSM while requiring a smaller number of transmit antennas, and outperformsIQSM by up to 2 dB when the same number of antennas are used.