We address the problem of blind carrier frequency-offset (CFO) estimation in quadrature amplitude modulation,
phase-shift keying, and pulse amplitude modulation
communications systems.We study the performance of a standard
CFO estimate, which consists of first raising the received signal to
the Mth power, where M is an integer depending on the type and
size of the symbol constellation, and then applying the nonlinear
least squares (NLLS) estimation approach. At low signal-to noise
ratio (SNR), the NLLS method fails to provide an accurate CFO
estimate because of the presence of outliers. In this letter, we derive
an approximate closed-form expression for the outlier probability.
This enables us to predict the mean-square error (MSE) on CFO
estimation for all SNR values. For a given SNR, the new results
also give insight into the minimum number of samples required in
the CFO estimation procedure, in order to ensure that the MSE
on estimation is not significantly affected by the outliers.
This program simulates the bit-error-rate (BER) performance of OSTBC
with L=4 antennas over the frequency flat Rayleigh block fading channel
The code is developed for real orthogonal design, code rate 1/2
modulation- 16 QAM with gray coding resulting in 2 bits/sec/Hz.
This project aim was to build wireless software modem for data communication
between two computers using an acoustic interface in the voice frequency range (20Hz–
20,000Hz). The transmitting antenna is a speaker (frequency response of: 90Hz –
20,000Hz) and the receiving antenna is a microphone (frequency response of: 100Hz –
16,000Hz). The test files used as information files were text files.
This goal was attained both in an incoherent scheme and in a coherent scheme.
Build under Matlab code, our modem uses OFDM (orthogonal frequency division
multiplexing) modulation, synchronization by LMS sequence, channel estimation (no
equalizer) via pilot tones. The symbols are either PSK or ASK for a constellation size of
2 or 4. To optimize the probability of error, these symbols were mapped using Gray
mapping.
Report
In this letter, the error performance of an ultra-wideband (UWB) system with a hybrid pulse amplitude and position modulation (PAPM) scheme over indoor lognormal fading channels is analyzed. In the PAPM UWB system, input data is modulated onto both the pulse amplitudes and pulse positions.
用fpga實現的DA轉換器，有說明和源碼，VDHL文件。
A PLD Based Delta-Sigma DAC
Delta-Sigma modulation is the simple, yet powerful,
technique responsible for the extraordinary
performance and low cost of today s audio CD
players. The simplest Delta-Sigma DAC consists of a
Delta-Sigma modulator and a one bit DAC. Since,
both of these components can be realized using
digital circuits, it is possible to implement a low
precision Delta-Sigma DAC using a PLD.
The PWM_1 project is a simple program for the STM32F103RBT6
using Keil MCBSTM32 Evaluation Board and demonstrating
the use of PWM (Pulse Width modulation) with Timer TIM4.
This project allows you to learn communication systems in greater depth. It contains the Simulink files (*.mdl) which are block design files of various communication systems such as AM, DSB-SC, FM, PLL, Data Acquisition, Digital Data Transmission, PCM and Delta modulation.
The idea here is to implement experiments of a traditional communication lab using Simulink.
Most of the block diagrams are self explanatory. More information on the systems and their implementation can be found in the word documents included in the lab directories
This a GUI based system. The GUI is invoked from the command line by typing "ui_start". The GUI is self explanatory.
Tool tips are given in blue color. The cursor needs to be positioned on these for detailed explanation. The main file is
"runsim.m". In these simulations the SISO option is not explicitly given. This is because the SISO result for a particular
type of modulation is shown in every plot for purposes of comparison.
This software has been tested on MATLAB version 6.0 and above with signal processing and communication toolbox options.
