نتایج جستجو برای: signal resolution

تعداد نتایج: 676645  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند 1388

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

Journal: یافته 2006
ahmad Bitavafan-Rahabi, hosein Rajabi, mohammad reza Farsi-nejad, samira Resaneh,

Background: The nuclear medicine systems are very sensitive to the variation of the magnetic field. Photomultiplier tubes amplify low energy light signal and change it into electrical current. Low magnetic field can produce some variations in uniformity and special resolution of SPECT systems. In this study, we tried to evaluate the effects of magnetic field on the function of nuclear medic...

ژورنال: فیزیک زمین و فضا 2018

Time-frequency filtering is an acceptable technique for attenuating noise in 2-D (time-space) and 3-D (time-space-space) reflection seismic data. The common approach for this purpose is transforming each seismic signal from 1-D time domain to a 2-D time-frequency domain and then denoising the signal by a designed filter and finally transforming back the filtered signal to original time domain. ...

Journal: :journal of medical signals and sensors 0
akbar pashaei mohammad reza yazdchi hamid reza marateb

in current years, the application of biopotential signals has received a lot of attention in literature. one of these signals is an electromyogram (emg) generated by active muscles. surface emg (semg) signal is recorded over the skin, as the representative of the muscle activity. since its amplitude can be as low as 50 µv, it is sensitive to undesirable noise signals such as power‑line interfer...

Journal: :رادار 0
روح اله رمضانی مجید اخوت

s is a time-frequency transform based on the concept of short-time fourier transform and wavelet transform. the main property of this transform that separate it from the discrete short-time fourier transform is variable frequency resolution. but in this transform the change of resolution of high frequencies to low frequencies is very high. so another transform as a modified s transform is intro...

In this paper excitation characteristics of the Liquid Crystal (LC) capacitive chemical and biological sensor are examined and the optimum frequency and voltage range for the sensor interface are introduced. Interdigitated capacitor has been used for the sensor capacitance measurement and two different molecular orientations, homeotropic and homogenous, have been considered. The LC sensor capac...

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