Tags: style blog http io color ar os for SPI. QPSKorthogonal Phase shift keying (quadrature Phase Shift keying) is referred to as "QPSK" and is a digital modulation method. It is divided into two kinds: absolute phase shift and relative phase shift. Because of the phase ambiguity problem in the absolute phase shift, the relative shift phase is used to dqpsk the method. It has been widely used in wireless co
PCM (Pulse-code modulation) Pulse coding modulation, pcm Pulse Coding modulation
In audio processing, we often hear PCM data. What is PCM Data?PCM data is a digital signal after the analog signal passes through PCM. PCM is the process of converting the audio signal from analog signal (time continuous, value continuous) to digital signal (time discrete, value dis
obtained by the minimum modulation index (0.5) quadrature signal, and "fast" refers to the given same frequency band, the MSK can be higher than the 2PSK data transmission rate, and in the band outside the spectral component is faster than the 2PSK attenuation. The MSK signal has the following characteristics:1. The MSK signal is a constant envelope signal;2. At the time of the code element conversion, the phase of the signal is continuous, and the s
calculation of MCS, modulation order, encoding rate, spectral efficiency relationship table
Reference URL: http://4g-lte-world.blogspot.tw/2012/12/transport-block-size-code-rate-protocol.html
Reference URL: http://blog.richliu.com/2013/10/22/1545/
(1) Premises:
Therefore, the efficiency can be simplified to the following formula:
tbs= size of the transfer block (table 7.1.7.2.1-1)
crc= the number of bits that are attached for error checking =24
Ask modulation simulation circuit:Device Selection:Select the signal source of the voltage-controlled sine wave in the sources->controlled_valtage_sources->voltage_controlled_sine_wave.Parameter settings:Set the signal generator to produce 1KHz, duty-free ratio 50%, amplitude of 5V square wave signal.Set the voltage control sine wave signal source control array -5v corresponding frequency 0hz,5v corresponds to 10khz,output peak low value = 0v,output P
FM) by analyzing the variation in amplitude or fre Quency. The same rules of amplitude and frequency variations is followed when transmitting or receiving the data signal.From the above methods of AM and FM modulations different forms of radio modulations is derived. The On-off keying (OOK) technique described above is a derived form of AM modulation.Frequency hopping Spread Spectrum (FHSS) is a advanced form of FM modulation. Other
This is my maiden post, will also write more ICT blog. Today for everyone presented MATLAB simulation BPSK modulation of the codes:Clear ALL;CLC;Snr_db=1:1:9;snr=10.^ (SNR_DB./10);Size=length (snr_db);A=ones (1,size);% fixed a, variable sigma definedSigma=sqrt (1./(2*snr));%a=1n=10000;S=randi ([0,1],1,n);s1=2*s-1;S2=zeros (1,n);N_errb=zeros (1,size);For I=1:1:sizeN=sigma (i). *RANDN (1,n);Y=s1+n;For J=1:1:nIf Y (j) >0S2 (j) = 1;Else Y (j) S2 (j) = 0;E
A. 4FSK principleDMR System, digital trunking communication system. The DMR protocol adopts a modulation mode of 4FSK, which is a constant envelope modulation, which transmits 2,400 symbols per second and each symbol carries two bits of information. The maximum frequency offset d is defined as follows:d = 3h/2t,h represents the frequency offset factor for each modulatio
The ADSL access technology is still quite common. So I studied the modulation knowledge in the ADSL access technology. I would like to share it with you here, hoping it will be useful to you. Asypolicric Digital Subscriber Line (Asymmetric Digital user Line) is an Asymmetric copper access network technology. It uses Digital encoding technology to obtain large data transmission rates from existing copper telephone lines, at the same time, it does not i
made, then the mobile phone receives data with support from the hardware channel!3. How to modulated data
When it comes to signal modulation and demodulation, many people will think of the Radio. Yes, the reason why the radio can hear singing thousands of miles away is that it uses electromagnetic waves as the transmission media, loads the signal of a sound source to an electromagnetic wave through specific modul
Original link: http://www.elecfans.com/analog/20120509270848_4.htmlAmplitude modulation and detection circuitsRadio and radio communication is the use of modulation technology to add low-frequency sound signal to the high-frequency signal emitted. The process of restoring in the receiver is called demodulation. wherein the low frequency signal is called the modulation
Modern mobile communication systems all use digital modulation technology. Because digital communication is flexible in network construction, it is easy to use digital error control technology and digital encryption to facilitate integration and access the Integrated Service Network (ISDN ), therefore, all communication systems are crossing the data in analog mode. As a part of the entire network, mobile communication will inevitably transition from a
Reprinted:
What is PWM (Pulse Width Modulation): http://www.shenmeshi.com/Science/Science_20070315160722.html
PWM (Pulse Width Modulation)-pulse width modulation (PWM) is an on/off type regulated power supply application. It is a very effective technology that uses the digital output of a microprocessor to control analog circuits.
With the development of electro
How to disable Dynamic Frequency Modulation of CPU 1. how can I check whether the dynamic frequency modulation function www.2cto.com is enabled on the current OS and whether the clock speed of all cores is the maximum CPU speed: grep-E '^ model name | ^ cpu MHz'/proc/cpuinfo can also be used through: lsmod | grep cpufreq_ondemand to check whether the cpufreq_ondemand module is loaded or through: service --
First, FM modulation 1, the code is as follows:CLC,CLEAR;FM= -; %modulation signal frequency (Hz) Am=0.5; %modulation signal Amplitude FC= 5e3; %Carrier Frequency (Hz) Ac=1; %Carrier amplitude MF=5; %FM Index%%%FIRSTLYKF= MF *2* PI * FM/AMDIATF= KF *AmB=2* (MF +1) *FM%%%SECONDLYFS= 64e3; %Sample Rate N= the; %number of sample points T= (0: N-1)'/fs;% time T%plott
I. GMSK modulation signal generation, software radio DSP implementation processTwo. Gmsk demodulation, one-bit differential demodulation, DSP implementation processThree. Based on the software radio architecture idea, has been implemented and optimized DSP, in line with the projectFour. ReferencesThe DSP realization of GSM communication system Gmsk"Gmsk modulation and demodulation and its TMS320C6XXXDSP rea
With the rapid development of the Internet, communication technology is experiencing a huge revolution, because the number of users accessing the network rapidly increases. As a network connected to the end users in the communication network, the access network has become a hot topic in network technology.
Currently, the main access technologies include hybrid fiber/coaxial (HFCs) access technology, optical fiber access technology, copper wire access technology and wireless access technology. Co
Pulse Width Modulation, or PWM, is a technique for getting Analog results with digital means. digital control is used to create a square wave, a signal switched between on and off. this on-off pattern can simulate voltages in between full on (5 volts) and off (0 volts) by changing the portion of the time the signal clock Ds on versus the time that the signal clock DS off. the duration of "on time" is called the pulse width. to get varying analog value
Recently want to use Raspberry Pi control model of the ESC, so studied the next PWM, seemingly control the ESC is troublesome, because the ESC needs to send a few specific signals to start, and then to enter the control mode, today first understand PWM, slowly toss. The following program pro-test is available, I use the Raspberry Pi model B,12gpio port is the 6th pin outside.Pulse width modulation (PWM) refers to the digital output of the microprocess
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