Experimental Study of a Signal Modulation Method to Improve eLORAN Data Channel Communications

There are mainly two types of data modulation methods used for enhanced LOng-RAnge Navigation (eLORAN) systems: pulse position modulation (PPM) and supernumerary interpulse modulation (SIM). The typical application for PPM is tri-state PPM (3S-PPM), also known as Eurofix. The typical application for SIM is ninth pulse modulation. Both of these methods are phase modulation methods. Phase modulation coding, a very mature technology, is used at present. To achieve a better demodulation success rate of eLORAN digital modulation signals at longer distances, a method of using the transmitting station duplex mode to transmit a digital modulation pulse group after LORAN-C transmitting a pulse group is proposed to realize modulation pulse on–off modulation. In this method, a broadcasting experiment was performed on the BPL (The call sign of eLORAN time service system in China) broadcaster station. After monitoring, a good receiving demodulation effect was initially obtained.

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Overcoming of a Resonance Stall and the Minimization of Amplitudes in the Transient Resonance of a Vibratory Machine by the Phase Modulation Method

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3204503 ◽

2010 ◽

Vol 132 (5) ◽

Cited By ~ 1

Author(s):

J. Michalczyk ◽

Ł. Bednarski

Keyword(s):

Angular Velocity ◽

General Model ◽

Phase Modulation ◽

Modulation Method ◽

Practical Implementation ◽

Control Value ◽

Unbalanced Rotor ◽

Transient Resonance ◽

Modulation Methods ◽

The Impact

The present paper elucidates the difficulties faced in the practical implementation of phase modulation methods in the form that was presented by Wang et al. and in the actual systems where the motor driving moment is the control value. A more general model, which takes into consideration the impact of machine vibrations on the rotor angular velocity, was developed. The modification of the phase modulation method is also proposed. The usefulness of such an approach for shaping the transient resonance of the machines with an unbalanced rotor is proven by means of a simulation and an experiment.

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Application of FT-IR Step-Scan Photoacoustic Phase Modulation Methods to Keratin Fibers

Applied Spectroscopy ◽

10.1366/0003702953963508 ◽

1995 ◽

Vol 49 (3) ◽

pp. 361-366 ◽

Cited By ~ 12

Author(s):

Lucia E. Jurdana ◽

Kenneth P. Ghiggino ◽

Ian H. Leaver ◽

Peter Cole-Clarke

Keyword(s):

Phase Modulation ◽

Depth Profiling ◽

Protein Composition ◽

Modulation Method ◽

Ft Ir ◽

Keratin Fibers ◽

Saturation Effects ◽

Modulation Methods ◽

Lock In ◽

Optical Velocity

Step-scan FT-IR/PAS is shown to be a powerful tool for the nondestructive analysis of keratin fibers. Depth profiling studies were performed either by varying the optical velocity of the interferometer (scanning FT-IR/PAS depth profiling) or by a phase modulation method, utilizing a lock-in amplifier to separate the surface and bulk components of the signal phase. Both methods were shown to be capable of distinguishing spectroscopically between the cuticle and cortex of wool and hair fibers, the different spectral features being consistent with the differences in protein composition between these components. Phase-modulated spectra exhibited improved signal-to-noise ratios, with relatively little interference from saturation effects, compared with scanning FT-IR/PAS depth profile spectra.

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Research and Analysis of Phase Modulation Method of Standby Power Transmission Line Based on TSPST

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/772/1/012024 ◽

2021 ◽

Vol 772 (1) ◽

pp. 012024

Author(s):

Xuxin Wu ◽

Yili Liu ◽

Zheng Ren ◽

Weiming Liu

Keyword(s):

Transmission Line ◽

Phase Modulation ◽

Power Transmission ◽

Modulation Method ◽

Power Transmission Line ◽

Standby Power

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Sub-nanosecond one-way real-time time service system based on UTC

GPS Solutions ◽

10.1007/s10291-021-01089-z ◽

2021 ◽

Vol 25 (2) ◽

Author(s):

Meifang Wu ◽

Baoqi Sun ◽

Yuanxin Wang ◽

Zhe Zhang ◽

Hang Su ◽

...

Keyword(s):

Real Time ◽

Service System ◽

Time Service

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Application of Ultra Narrow Band Modulation in Enhanced Loran System

Sensors ◽

10.3390/s21134347 ◽

2021 ◽

Vol 21 (13) ◽

pp. 4347

Author(s):

Boyun Lyu ◽

Yu Hua ◽

Jiangbin Yuan ◽

Shifeng Li

Keyword(s):

Narrow Band ◽

Data Rate ◽

Modulation Method ◽

Phase Shift Keying ◽

Spectrum Utilization ◽

Frequency Domains ◽

Shift Keying ◽

Modulation Methods ◽

Binary Phase Shift Keying ◽

Signal Time

The Enhanced Loran (eLoran) system is valued for its important role in the positioning, navigation, and timing fields; however, with its current modulation methods, low data rate restricts its development. Ultra narrow band (UNB) modulation is a modulation method with extremely high spectrum utilization. If UNB modulation can be applied to the eLoran system, it will be very helpful. The extended binary phase shift keying modulation in UNB modulation is selected for a detailed study, parameters and application model are designed according to its unique characteristics of signal time and frequency domains, and it is verified through simulation that the application of this modulation not only meets the design constraints of the eLoran system but also does not affect the reception of the respective signals of both parties. Several feasible schemes are compared, analyzed, and selected. Studies have revealed that application of UNB modulation in the eLoran system is feasible, and it will increase the data rate of the system by dozens of times.

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Optimization of TSPWM for Common-Mode Voltage Reduction in Vehicular Electric Drive System

World Electric Vehicle Journal ◽

10.3390/wevj13010005 ◽

2021 ◽

Vol 13 (1) ◽

pp. 5

Author(s):

Shang Jiang ◽

Yuan Wang

Keyword(s):

Electric Drive ◽

Drive System ◽

Modulation Method ◽

Time Interval ◽

Common Mode ◽

Common Mode Voltage ◽

Electric Drive System ◽

The Common ◽

Modulation Methods ◽

Zero Voltage

Common-mode voltage can be reduced effectively by optimized modulation methods without increasing additional costs. However, the existing methods cannot satisfy the requirements of the vehicular electric-drive application. This paper optimizes the tri-state voltage modulation method to reduce the common-mode voltage for vehicular electric drive system applications. Firstly, the discontinuous switching issue during sector transition is analyzed. Under the limit of two switching times in one period, multiple alignments combination is proposed to address that issue. Secondly, the zero-voltage time intervals in different modulation ranges are explored. This paper proposes an unsymmetric translation method to reconstruct the voltage vector, and then the minimum zero-voltage time interval is controlled to enough value for safe switching. Finally, the proposed methods have been validated through experiments on a vehicular electric drive system. The results show that the common-mode voltage can be reduced effectively in the whole range with the optimized tri-state voltage modulation method.

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