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Showing 1 to 20 of 134 for “"Frequency shift"”.
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Data transmission by frequency-hopped multilevel frequency shift keying
Spread spectrum systems make use of radio frequency bandwidths which far exceed the minimum bandwidth necessary to transmit the basic message information.These systems are designed to provide satisfactory communication of the message information under difficult transmission conditions. …
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Design and Performance Analysis of Frequency-Shift Keyed Transmitter using Rapidly Tunable Lasers
Optical Frequency Shift Keying (FSK) is a modulation scheme that encodes data in the wavelength of a carrier signal. Due to the large amount of optical bandwidth available in the erbium, 1.55-𝜇m telecom band, FSK can potentially utilize a wide spectrum to achieve multi-Gb/s channel bandwidths. For …
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1S-2S spectroscopy of trapped hydrogen : the cold collision frequency shift and studies of BEC
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1999.
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Modeling, simulation and implementation of a non-coherent binary-frequency-shift-keying (BFSK) receiver-transmitter into a field programmable gate array (FPGA)
… array (FPGA) to implement a non-coherent binary-frequency-shift-keyed receiver-transmitter (BFSK-RT) that simulates the modulation of the SINCGARS radio, the RT-1523C. An FPGA successfully, and with very few resources, implemented the desired modulation and demodulation. Topics covered include …
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The resonant-frequency shift of a microwave cavity caused by the high-density plasma in semiconductors, as a function of magnetic field
Thesis: Sc. D., Massachusetts Institute of Technology, Department of Physics, 1959
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An analytical and experimental investigation of a frequency- shift-keyed signal generated by a phase-locked-loop with application to narrowband FSK
Narrowband communications systems employing frequency-shift-keyed (FSK) carrier modulation demand careful consideration of system transient responses. Discontinuous waveforms or their derivatives, such as produced by frequency modulation, can result in the generation of large transient currents and …
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Lewis Acid-Base Interactions. Part One: The Extension and Limitations of The Frequency Shift-Enthalpy Correlations of Hydrogen Bonding Systems. Part Two: Extension and Refinement of the E and C Correlation
Made available in DSpace on 2014-12-10T23:01:06Z (GMT). No. of bitstreams: 1 7114976.pdf: 3543850 bytes, checksum: 8d6a294c2dfd60076811ec9cf0a7ac59 (MD5) Previous issue date: 1970
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Design of sparse signaling schemes in fading wideband channels
The shift to the wideband regime due to the crowded frequency spectrum has resulted in a requirement for a different modulation scheme from previously used modulation schemes in order to succeed. Impulsive frequency shift keying, which is frequency shift keying with a duty cycle, is one such …
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Distributed fibre sensing using microwave heterodyne detection of spontaneous Brillouin backscatter
… due to the dependence of both the power and the frequency shift of the scattered radiation on these two quantities. Simultaneous temperature and strain sensing is possible if both the power and frequency shift are measured. Much work has been published which presents either power or frequency …
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Cascaded ROADM Filter Replication and the Effects of Statistical Variations in the Response of Cascaded ROADMs on 100 Gb/s DP-QPSK System Performance
… filter replication: bandwidth narrowing/ center frequency shift and passband impairments. Both were meant to model the effect of concatenating filters from a signal being transmitted through cascaded ROADMs. The real-time testing section was based around using a WaveLogic 3 real-time transceiver …
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Interacting Ultracold Alkali Atomic Fermion Gases and Radio-Frequency Spectroscopy
The last chapter focuses on radio-frequency spectroscopy of multi component fermion gases. Rf experiments of 6Li and 40K are first reviewed. We show that rf experiments essentially measure spin correlation functions, and internal symmetries of the interparticle interactions constrain the rf …
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Spontaneous brillouin scattering quench diagnostics for large superconducting magnets
… Brillouin laser with very low noise as a frequency shifted local oscillator, the frequency shift of spontaneous Brillouin scattered light was measured using heterodyne detection. A pulsed laser was used to probe the fiber using Optical Time Domain Reflectometry (OTDR) to define the spatial …
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Nonlinear Photonics in Waveguides for Telecommunications
… systems. Similarly, an optically tunable frequency shift was observed using this system. Pulses experienced a full spectral bandwidth shift at low peak pump powers when utilizing the Raman-induced frequency shift and slow light effects. Numerical simulations of the pulse-propagation …
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Study and Design of an Electro -Optic Frequency Shifter for Dynamic and Continuous Tuning of Short Pulses of Light
… to improve the device operation and increase the frequency shift obtained with controlled spectrum distortion levels were proposed and tested showing promising results.
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Performance of Digital Communications Over Selective Fading Channels
… of the performance of binary differential phase-shift keyed (DPSK) and binary frequency-shift keyed (FSK) communications with primary emphasis on the effects of intersymbol interference produced by the frequency-selective character of WSSUS fading channels.
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Chromatic dispersion measurement in single-mode optical fibers by acousto-optic modulation and phase detection
… collected by using an acousto-optic modulator to frequency-shift laser light passed to an optical heterodyne. Theoretical developments include a frequency-domain calculation technique for interpreting empirical results. The system is proven infeasible, however, due to inherent noise sensitivity
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Formation and decay of a Bose-Einstein condensate in atomic hydrogen
… of atomic hydrogen has the same collisional frequency shift of the two-photon IS-2S resonance as a noncondensed gas at the same density. This finding contradicts theoretical predictions of the collisional shift for trapped samples with a homogeneous density. We suggest that elastic collisions …
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Error-rates of digital signaling with coherent and noncoherent detections
… data communication systems, namely, amplitude-shift keying (ASK), frequency-shift keying (FSK), and phase-shift keying (PSK), for both binary coded and M-ary coded transmissions are presented in this paper. The analysis is limited to only nonfading received signal in additive Gaussian noise. …
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Performance analysis of Binary FSK signals with L-Fold diversity selection combining techniques in a Nakagami-M fading channel
… performance analysis of a non-coherent Binary Frequency Shift Keying (BFSK) receiver using Selection Combining techniques over a frequency non-selective, slowly fading Nakagami channel. These techniques are independent of the number of diversity branches, so simpler receivers can be employed. …
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Multi-Physical Study of MEMS Resonators and Oscillators
… pressures. It is demonstrated that the resonant frequency of such devices follows particular trends in response to the changes in the surrounding gas and its pressure. A mathematical model has been derived to explain the damping dependent frequency shift characteristic of TPO. The solution of the …
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