• Study Resource
  • Explore
    • Arts & Humanities
    • Business
    • Engineering & Technology
    • Foreign Language
    • History
    • Math
    • Science
    • Social Science

    Top subcategories

    • Advanced Math
    • Algebra
    • Basic Math
    • Calculus
    • Geometry
    • Linear Algebra
    • Pre-Algebra
    • Pre-Calculus
    • Statistics And Probability
    • Trigonometry
    • other →

    Top subcategories

    • Astronomy
    • Astrophysics
    • Biology
    • Chemistry
    • Earth Science
    • Environmental Science
    • Health Science
    • Physics
    • other →

    Top subcategories

    • Anthropology
    • Law
    • Political Science
    • Psychology
    • Sociology
    • other →

    Top subcategories

    • Accounting
    • Economics
    • Finance
    • Management
    • other →

    Top subcategories

    • Aerospace Engineering
    • Bioengineering
    • Chemical Engineering
    • Civil Engineering
    • Computer Science
    • Electrical Engineering
    • Industrial Engineering
    • Mechanical Engineering
    • Web Design
    • other →

    Top subcategories

    • Architecture
    • Communications
    • English
    • Gender Studies
    • Music
    • Performing Arts
    • Philosophy
    • Religious Studies
    • Writing
    • other →

    Top subcategories

    • Ancient History
    • European History
    • US History
    • World History
    • other →

    Top subcategories

    • Croatian
    • Czech
    • Finnish
    • Greek
    • Hindi
    • Japanese
    • Korean
    • Persian
    • Swedish
    • Turkish
    • other →
 
Profile Documents Logout
Upload
(PPT, 328KB)
(PPT, 328KB)

... 1246MHz with the center frequency 1246MHz + n×0.4375MHz, where n spans the same range as for L1.GLONASS transmitter specs In the original GLONASS design, only obfuscated high-precision signal was broadcast in the L2 band, but starting with GLONASS-M, an additional civil reference signal L2OF is broa ...
投影片 1
投影片 1

... • As discussed before, the received signal consists of multiple copies of the transmitted signal when the channel is under frequency selective fading. • If the fading on different paths are independent, we can combine the contributions from different paths to enhance the total received signal power. ...
www.ijecs.in International Journal Of Engineering And Computer Science ISSN:2319-7242
www.ijecs.in International Journal Of Engineering And Computer Science ISSN:2319-7242

... arrangement of data and null sub-carriers is selected for transmission which gives the least PAPR value. The purpose of shifting the null sub-carriers to positions of data sub-carriers is that the inputs to IFFT changes which in turn gives us different output and hence different PAPR values. B. Impl ...
Energy Efficient OFDM Transmission Scheme based on Continuous
Energy Efficient OFDM Transmission Scheme based on Continuous

- Leeds Beckett Repository
- Leeds Beckett Repository

... of the PLC service. The best suitable modulation technique for PLC system is an Orthogonal Frequency Division Multiplexing (OFDM) [2]. OFDM is a Multi-Carrier modulation scheme in which a single high rate data-stream is divided into multiple low rate data-streams. It is also modulated by using sub-c ...
Enhanced fourth-power algorithm for phase estimation with
Enhanced fourth-power algorithm for phase estimation with

... In particular, from the average phase θn (k), the superiority of the phase estimation algorithm with separated compensation in accordance to frequency can be clearly observed. The impairments have different effects on the DDO-OFDM signal at various frequencies, and a phase estimation algorithm with ...
PLC G3 Physical Layer Specification Speaker : Jiun
PLC G3 Physical Layer Specification Speaker : Jiun

... J = ( j * n_j + i * n_i ) % n I = ( i * m_i + J * m_j ) % m ...
Timing Synchronization in Cognitive Radio Systems Using Improved
Timing Synchronization in Cognitive Radio Systems Using Improved

... Television bands (UHF/VHF). Orthogonal Frequency Division Multiplexing (OFDM) being one of the most flexible schemes for the implementation of cognitive radio technique is used in WRAN as a physical layer modulation scheme. In OFDM, several carriers are employed within an allocated spectral bandwidt ...
Coherent Optical OFDM System or Long-Haul Transmission
Coherent Optical OFDM System or Long-Haul Transmission

... used in optical networks, but spectral efficiency obtained is very less. Recently, many advanced modulation formats in signal amplitude, phase, and polarization has been investigated to increase the capacity of the system. Coherent detection when combined with the advance modulation technique can ea ...
Test bed for Selecting Optimum Sequences for
Test bed for Selecting Optimum Sequences for

... significantly without additional bandwidth or transmit power by placing multiple antenna elements both on transmitter or receiver, the technology referred to as Multiple Input Multiple Output (MIMO). Increased spectral efficiency through spatial multiplexing, improved link reliability through antenn ...
ML Detection with Symbol Estimation for Nonlinear Distortion of OFDM Signals
ML Detection with Symbol Estimation for Nonlinear Distortion of OFDM Signals

... subcarriers. As a result, multicarrier systems are more sensitive than the single-carrier systems to the presence of nonlinearities when such a signal is input to a nonlinear amplifier. Due to the large dynamic range of modulated signal, the nonlinear distortion at the power amplifier of transmitter ...
Spectral Efficiency and Receiver Sensitivity in Direct Detection Optical-OFDM
Spectral Efficiency and Receiver Sensitivity in Direct Detection Optical-OFDM

... Optical transmission systems employing orthogonal frequency division multiplexing (OFDM) have gained considerable research interest because OFDM can combat fiber chromatic dispersion [1,2] and has the capability to use higher level modulation formats to increase spectral efficiency [3]. In direct de ...
Reducing the Peak to Average Power Ratio of Multicarrier
Reducing the Peak to Average Power Ratio of Multicarrier

... into time{domain using the inverse discrete Fourier transform (IDFT). The main advantage of OFDM is that, by introducing a \guard{period" [1] and using di erential encoding, reliable transmission over spectrally shaped channels is possible without any equalization. Unfortunately, because of the stat ...


... real output signal, complex conjugate symbols are created appropriately and fed into the IFFT, too. Moreover, half of the input of the IFFT around the DC value is filled with zeros to create an OFDM spectrum that avoids interference with second-order nonlinearity after squaring in the photo diode [1 ...
1

Orthogonal frequency-division multiplexing

Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL Internet access, wireless networks, powerline networks, and 4G mobile communications.OFDM is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. A large number of closely spaced orthogonal sub-carrier signals are used to carry data on several parallel data streams or channels. Each sub-carrier is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase-shift keying) at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth.The primary advantage of OFDM over single-carrier schemes is its ability to cope with severe channel conditions (for example, attenuation of high frequencies in a long copper wire, narrowband interference and frequency-selective fading due to multipath) without complex equalization filters. Channel equalization is simplified because OFDM may be viewed as using many slowly modulated narrowband signals rather than one rapidly modulated wideband signal. The low symbol rate makes the use of a guard interval between symbols affordable, making it possible to eliminate intersymbol interference (ISI) and utilize echoes and time-spreading (on analogue TV these are visible as ghosting and blurring, respectively) to achieve a diversity gain, i.e. a signal-to-noise ratio improvement. This mechanism also facilitates the design of single frequency networks (SFNs), where several adjacent transmitters send the same signal simultaneously at the same frequency, as the signals from multiple distant transmitters may be combined constructively, rather than interfering as would typically occur in a traditional single-carrier system.
  • studyres.com © 2025
  • DMCA
  • Privacy
  • Terms
  • Report