I ve written some many years ago dynamic Huffman algorithm to compress and decompress data. It is mainly targeted to data with some symbols occuring more often than the rest (e.g. having some data file consisted of 3 different symbols and their total number of occurence in that file s1(1000), s2(200), s3(30) so the total length of file is 1000+200+30=1230 bytes, it will be encoded assigning one bit to s1 and 2 bits to s2, s3 so the encoded length will be 1*1000+2*(200+30)=1460 bits=182 bytes). In the best case the file consisted of just one symbol will be encoded with compression ratio as 1:8. Huffman coding is used in image compression, however in JPEG2000 arithmetic codec is imployed.
Matlab is an ideal tool for simulating digital communications systems, thanks to
its easy scripting language and excellent data visualization capabilities. One of the
most frequent simulation tasks in the field of digital communications is bit-error-
rate testing of modems. The bit-error-rate performance of a receiver is a figure of
merit that allows different designs to be compared in a fair manner. Performing
bit-error-rate testing withMatlab is very simple, but does require some prerequisite
knowledge
This LDPC software is intended as an introduction to LDPC codes computer based simulation. The pseudo-random irregular low density parity check matrix is based on Radford M. Neal’s programs collection, which can be found in [1]. While Neal’s collection is well documented, in my opinion, C source codes are still overwhelming, especially if you are not knowledgeable in C language. My software is written for MATLAB, which is more readable than C. You may also want to refer to another MATLAB based LDPC source codes in [2], which has different flavor of code-writing style (in fact Arun has error in his log-likelihood decoder).
For C8051F330 This code example illustrates using the internal analog multiplexer to
measure analog voltages on up to 8 different analog inputs. Results are
printed to a PC terminal program via the UART.
％ DYNMODES calculates ocean dynamic vertical modes
％ taking a column vector of Brunt-Vaisala values (Nsq) at
％ different pressures (p) and calculating some number of
％ dynamic modes (nmodes).
％ Note: The input pressures need not be uniformly spaced,
％ and the deepest pressure is assumed to be the bottom.
This m file plots the time and frequency domain of UWB PPM(pulse position modulated) waveforms(monocycles and doublets) with different pulse recurring frequency (PRF)and information rates.
ofdm信道特性
Channel transmission simulator
Channel transmission simulator
％
％ inputs:
％ sig2 - noise variance
％ Mt - number of Tx antennas
％ Mr - number of Rx antennas
％ x - vector of complex input symbols (for MIMO, this is a matrix, where each column
％ is the value of the antenna outputs at a single time instance)
％ H - frequency selective channel - represented in block-Toeplitz form for MIMO transmission
％ N - number of symbols transmitted in OFDM frame
％
％ outputs:
％ y - vector of channel outputs (matrix for MIMO again, just like x matrix)
％ create noise vector sequence (each row is a different antenna, each column is a
％ different time index) note: noise is spatially and temporally white
The Universal Asynchronous Receiver Transmitter (UART) is a popular and widely-used device for data communication
in the field of telecommunication. There are different versions of UARTs in the industry.
This book is the culmination of more than 20 years of building, studying, and teaching real-time systems. The author’s travels have taken him to NASA, UPS, Lockheed Martin, the Canadian and Australian Defense Forces, MIT’s Charles Stark Draper Labs, and many other places. These visits and interactions with literally hundreds of students from such places as Boeing, Motorola, and Siemens have resulted in a wider understanding of real-time systems and particularly their real application. This book is, in essence, a compendium of these experiences. The author’s intent is to provide a practical framework for software engineers to design and implement real-time systems. This approach is somewhat different from that of other texts on the subject.
NIST Net – A Linux-based Network Emulation Tool, It is a raw IP packet filter with many controllable channel parameters such as packet loss ratio, jitter, bandwidth variation, delay, and network buffer size. To simulate different network environments
