We simulate uncoded BER of BPSK modulated
data as a function of SNR
-in an AWGN channel
-in a Rayleigh fading channel
-in an AWGN channel when direct sequence spreading
is used
and compare results to the theoretical ones.
We assume coherent receiver and perfect
synchronization.
SPREAD SPECTRUM MODULATION TECHNIQUES
-spread spectrum - those modulation methods that are producing a signal whose
spectrum is more wider than of the data signal, the occupied frequency band being
independent by the signal of data band.
-The signals with spread spectrum of direct sequence type BPSK (BPSK-DS-SS)
-The signals with spread spectrum of direct sequence type QPSK – DS–SS
- Frequency hopping spread spectrum signals (FH-SS)
This example program is the source code for the FT232BM Test Application from our Utilities page.
It can be used to test the handshaking lines on FT232BM based RS232/RS485/RS422 designs. This program can also be used for programming the external EEPROM over USB in a manufacturing environment. The test features require the test cable shown on ST_232_245.pdf to be connected.
Our D2XX direct drivers should be installed for this application. The code can be modified to fit your requirements.
To download the application source code , click here.
To download the test cable specification, click here.
this code is a implementation of the Discrete cosinuss transformation.
In this code I have used the direct méthode of calcul by used the equation without used the maatrix multiplication.
Universal.Data.Access.Components 2.50
Universal Data Access Components (UniDAC) is a library of components that provides direct access to most popular database servers from Delphi, Delphi for .NET and, C++Builder. UniDAC can work with such servers as Oracle, Microsoft SQL Server, MySQL, Interbase, Firebird. The UniDAC library is designed to help programmers develop faster and cleaner cross-database applications. UniDAC is a complete replacement for such standard universal technology as dbExpress. UniDAC is a handy in use and efficient data access solution bringing into play many features specific to each server.
In 揚erformance of multi-carrier DS CDMA Systems?we apply a multi-carrier signaling technique to a direct-sequence CDMA system, where a data sequence multiplied by a spreading sequence modulates multiple carriers, rather than a single carrier. The receiver provides a correlator for each carrier, and the outputs of the correlators are combined with a maximal-ratio combiner. This type of signaling has the desirable properties of exhibiting a narrowband interference suppression effect, along with robustness to fading, without requiring the use of either an explicit RAKE structure or an interference suppression filter.
本系統分電壓測量和信號產生輸出兩大部分，電壓測量部分以模擬電路為主，配合放大模塊、A/D轉化模塊、顯示模塊；通過凌陽單片機進行數據處理，在誤差允許范圍內顯示測量電壓值。信號產生以直接數字式頻率合成器(direct Digital Frequency Synthesis,簡稱DDS或DDFS)為核心，經過AT89S52對DDS芯片內部進行控制，使之輸出標準正弦波形，利用編程實現頻率預置、步進，達到電壓輸出頻率的可調節步進。通過調試與測量完成了題目的基本部分和全部發揮部分的要求并有自己的創新
