P3.18. An analog signal xa(t) = sin (100πt) is sampled using the following sampling intervals. In
each case plot the spectrum of the resulting discrete-time signal.
Ts= 0.1 ms, Ts= 1 ms, Ts = 0.01 Sec
Wi-Fi pollution, or an excessive number of access points in the area, especially on the same or neighboring channel, can prevent access and interfere with the use of other access points by others, caused by overlapping channels in the 802.11g/b spectrum
The Schumann resonance frequencies are a set of eigenmodes in the extremely low frequency (ELF) portion of the electromagnetic field spectrum. These frequencies are only present for planetary-like bodies with a substantial ionosphere acting as a perfect electric conductor, thus forming a resonance cavity with the surface. In this example, the Schumann resonance frequencies for the Earth are calculated.
The Open Radar Data Acquisition (ORDA)
subsystem replaces the current WSR-88D Radar
Data Acquisition subsystem with improved
receiver and signal processing hardware and with
improved user interface, signal processing and
diagnostics software. This paper will discuss the
input data from the digital receiver, the ORDA
signal processing, and the data output from the
ORDA hardware. Specifications of the ORDA
digital receiver will be presented. The paper
outlines the critical radar signal processing flow
and provides analysis of new spectrum width
computations and clutter filtering schemes used in
the ORDA system. Where appropriate, ORDA
performance enhancements, data quality
improvements and reliability and maintenance
improvements will be highlighted.
Use
the fast Fourier transform function fft to analyse following signal. Plot the original signal, and the magnitude of its
spectrum linearly and logarithmically. Apply Hamming window to reduce the
leakage.
.
The hamming window can be coded in Matlab as
for n=1:N
hamming(n)=0.54+0.46*cos((2*n-N+1)*pi/N);
end;
where
N is the data length in the FFT.
調制解調課程設計 16QAM調制解調代碼。包括星座圖，頻譜分析，誤碼率分析。-16QAM modulation and demodulation curriculum design code modulation and demodulation. Including constellation, spectrum analysis, bit error rate analysis.
Licensed spectrum remains 3GPP operators’ top priority to deliver
advanced services and user experience
Opportunistic use of unlicensed spectrum is becoming an important
complement for operators to meet the growing traffic demand
Moving forward 3GPP operators will have two options to offload
traffic to unlicensed spectrum:
1. Wi-Fi (via LTE/Wi-Fi interworking)
2. LTE over unlicensed
It will then be up to each individual operator to choose which
approach to use, which will depend on a number of factors
The growing interest for high data rate wireless communications over the last few decades
gave rise to the emergence of a number of wideband wireless systems. The resulting scarcity
of frequency spectrum has been forcing wireless system designers to develop methods that
will push the spectral efficiency to its limit.
