China
Africa
Explore chapters and articles related to this topic
Telemedicine Technology
Published in Rajarshi Gupta, Dwaipayan Biswas, Health Monitoring Systems, 2019
Telecommunication technology involves the transmission of signal through a communication channel, which could be a coaxial cable, free space, optical fiber, etc. In transmission of digital data, it is required to convert or encode the data into analog signal or symbols. At the receiving end, the encoded analog signal is decoded in the form of digital data. To bring the bandwidth of the transmitting signal within the bandwidth of the communication channel, it is required to modulate the input signal. At the receiving end, the inverse operation, called demodulation, is carried out to reconstruct the signal in its original form. Usually, in a modulation technique, a carrier sinusoidal signal is used whose amplitude, shifts in frequency, or phase vary in proportion to the input signal, which is referred to as amplitude, frequency, and phase modulation, respectively.
Magnetic Recording Fundamentals
Published in Joseph Cavanagh, Digital Design and Verilog HDL Fundamentals, 2017
In the phase encoding (PE) method, a transition is generated at the beginning of every bit cell to indicate the state of the bit in that cell: a positive transition indicates a 1 bit; a negative transition indicates a 0 bit. This provides a way to obtain self-clocking. Phase encoding is also referred to as phase modulation.
Mathematical Preliminaries
Published in Frank Y. Shin, Digital Watermarking and Steganography, 2017
for x, y = 0, 1, 2,…,N − 1. The DFT can be used for phase modulation between the watermark image and its carrier, as well as for dividing the image into perceptual bands to record the watermark. The DFT uses phase modulation instead of magnitude components to hide messages since phase modulation has less visual effect. Furthermore, phase modulation is more robust against noise attack.
The Design and Analysis of the Sidelobe Reduction Filter for Polyphase Frank Codes
Published in IETE Journal of Research, 2023
A Balaraju, S. P. Singh, Dhiraj Sunehra
Two types of pulse compression techniques are widely used i.e. (i) the frequency modulation technique and (ii) the phase modulation technique. Frequency modulation technique such as Linear Frequency Modulation (LFM) has a demerit of range-Doppler coupling so it is difficult to achieve a range resolution and a velocity resolution simultaneously. The other widely used choice of pulse compression is the phase modulation technique for discriminating closely spaced targets, in pulse compression radar systems. In the phase modulation technique biphase or polyphase codes are used. In biphase coding the phases are either 0° or 180°, whereas, in the well-known polyphase codes, phases are harmonically related [1–3]. Widely used polyphase codes are P1, P2, P3, P4, and Frank codes, etc., which are examples of harmonically related polyphase codes. Although the sidelobes of these codes are well controlled, in many situations, to avoid the masking of small targets present near the large target, further reduction in sidelobes is required. Therefore, in this paper the Frank code is considered and PSL is reduced by implementing a sidelobe reduction filter (SRF). In Section 2.1 the Frank code is explained.