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What's CFO(carrier frequency offset)? What mean? Why use it?
in OFDM sytems carrier frequency offset can occur due to doppler shift and local oscillator mismatch. you have understood the first part. When the baseband signal is converted to RF signal at the Tx, there will be a oscillator used to generate the RF carrier wave. Now, at the Rx end, there will be a similar oscillator (...)
I find that in some algorithm the received signal(atfer matched filter) is expressed as: r(t)=∑Sk*exp{j*(Δωt+Θ)}*g(t-kT-τ)+n(t) 2 questions: 1, why is Sk a complex array? If so, it will impact the angle of correlation of r(n)(sampled) and the final offset not only contain the carrier frequency (...)
Did you mean where frequency offset is more than 1/2 of the carrier spacing in the preamble?
please explian me synchronisation and frequency offset problem in OFDM
it means that @10 KHz offset we measure the phase noise at carrier frequency plus (+) or minuse (-) 10khz? is it truse?
ok fine but what about carrier recovery?
I can't understand your code, and maybe I am wrong but it is probably the code is completely wrong. At least there should be a modulation signal such as random bit sequence. And then the bit sequence is modulated with QPSK format on a carrier. Then the frequency offset should be added to the carrier. You can assume the (...)
Hi all, I'm implementing STBC-MIMO and MIMO-OFDM system using SDRs. Before doing actual coding, I'm working on MATLAB simulation of CFO estimation and recovery and channel estimation. I'm reading some Dr. Giannakis' papers about joint CFO and channel estimation. Besides Dr. G, I know that many people have researched joint CFO and channel es
Hi greeting.. At digital receiver, carrier frequency offsets cause rotating constellation plot. Can someone explain me how this is visualized in mathematical equation. :) PN
The following code is used to estimate and correct the frequency offset errors for a single carrier system %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% freqoffset = 0; phaseoffset = 0; hPFO = comm.Phasefrequencyoffset('frequencyoffset', (...)
Anyone could give me some idea about the reason of frequency offset and how to reduce it?
Hi all I have a question about the SSB receiver (Single sideband). Does one have to know the carrier frequency a priori, or is there a way to recover the carrier frequency even if it is not sent ?? (Cannot be the case, forget it.) But what does the so called Beat frequency oscillator do ? Kindest (...)
QPSK modulation scheme breaks the data stream in two parallel data streams with a 1/2 data rate. If you are regarding 400MB as the main data stream, you will have applied to the modulator I and Q 200MB, what means a maximum modulating frequency equal to 100MHz. Therefore, theoretically, you would be able to use a 100MHz carrier. However by using t
could anyone tell me: if use external crystal as a reference clock, the frequency offset of this crystal is important in a wireless transmitter. what's the special concern on "frequency offset"? It impact which performance of a wireless transmitter? if when: Fref=12MHz, frequency (...)
hi everybidy, i have simulated a code in matlab for the demodulation of ofdm signal (dab). In the synchronisation process, i found the clock offset of 13.035 khz in the spectrum after downconversion. i used a nco to remove the frequency offset. Now when i differentially decode the symbols, i get 5th and 6th symbols corrupted. I think this (...)
Dear Friends, I have a project for a high school, is needs one remote controller to control two lower power device in school. The transmitted distance is about 500~1000m only, the power of my transmitter is about 300~500mW and the operating battery is 9V battery. Can I use 315MHz carrier frequency without any approval in HK?? (such as, FCC, or..
Hi I am doing QPSK Transceiver as my FYP. I am confused about the relation between QPSK Data rate and the transmitter(antenna) carrier frequency. I am to transmitt and receive a voice signal upto 1Km. what rate of qpsk and what frequency of antenna should i use.......?
In psk signals generally carrier frequency Fc=(nc/Tb) nc-any constant integer Tb-baud rate Then in B.201B,V.27ter ALT and V.27bis ALT modem protocols carrier frequency is 1800Hz and baud rate is 1200.How is it possible.
I am going to check it out Thanks dude! By the way, how could the 2nd or 3rd order PLL get ride of the frequency offset? Since it is impossible to do the carrier recovery in DSSS due to the low SNR.
Is any one have code for estimation of frequency offset in STBC-OFDM please send me i am doing my M.Tech project on that is urgent for me.....
What does this term "residual carrier frequency" stand for? Thanks.
Hi to all experts at here, would like to ask about this question. When trying to find the frequency offset using equation in Myer's textbook, "Digital Communication Receivers": FTs=arg{sum{ r(kTs)r*((k-1)Ts)}, where F is the frequency offset estimation I want to find. Must the r in symbol or samples rate?? I had (...)
The properties and the behavior of a medium in response to electromagnetic waves are depended to the frequency of the wave. for example in coppers wires, we have slight attenuation per length for low frequencies like telephone lines, but for high frequencies we have very high attenuation. wireless channel is exactly the same but more complicated be
Hi, Currently, I am doing Baseband frequency offset estimation in matlab. However I had encounted a major problem. At low SNR, my algorithm could not estimate the offset. Anyone can tell me which steps I had missed out in my code? Hope the experts out there can help. This is my matlab code: Ain=sign(randn(1,1024)); %generate +/- 1 (...)
One thing still confuse me. How different audio frequency at a same time modulate single carrier frequency. I mean a 100MHz FM transmitter is broadcasting Music, music contains audio frequency from 1KHz to 18KHz, so my question is how a multiple audio frequency modulate single RF carrier at (...)
Please share your views regarding the reasons why there appears frequency offset in coherent detection of Pilot Signals.
Hi there, i wish to built a simple receiver to receive 315Mhz carrier frequency, don't care the signal as long as the it detected 315Mhz carrier frequency, the MCU will trigger the LED. Since this is my final year project, i don't wish to use the rf module or MAX1471. For receiving 315Mhz i will use either LC circuit, SAW (...)
Hi, I am trying an algorithm for CFO cancellation. I would like to know how well the algorithm performs with respect to the CFO required for commercial systems. Unfortunately, after googling a lot (web+scholar) I could not find any proper table/list/article that defines what is the allowed CFO in relevant applications. I believe there sho
can any one plz tell me any site on which i can get some details about carrier frequency amplifier.......
hi, Can someone explain how I can compensate for sampling clock frequency offset (SCO) using fractional-delay interpolation? In OFDM basebnad receiver design book they said that you can use fractional-delay interpolation filter to compensate SCO but of course they forgot to write about. Let's say I have a ramp signal (it will be easier for me
What is Eye Scan Test and frequency offset test and how these tests are done?
Hi, I would like to generate a carrier frequency in the range of 20KHz - 500KHz in steps of 0.5KHz means that it should be programmable in such a way that we can choose any desired frequency in between the range. for example 20KHz/20.5KHz/21KHz/21.5KHz... 498KHz/498.5KHz/499KHz/499.5KHz/500KHz. Looking forward for your valuable (...)
I need help to understand carrier frequency for QPSK. For QPSK, are symbol rate and carrier frequency always the same? I think so since basis functions are cosine and sine (at carrier frequency), and each cycle period brings phase information. Please give any comments if i'm correct, (...)
hi in amplitude modulation carrier frequency is much higher than the modulating/information signal (the signal which is to be transmitted). what will happen if carrier frequency is equal to modulating signal? what will happen if carrier frequency is less than modulating signal?
i'm designing a baseband processor for zigbee/ieee 802.15.4.but i don't know that if i use gardner method for timing recovery anymore i need a frequency offset cancellation part in my baseband processor???while zigbee must tolerate +/- 45 ppm frequency offset. and in practical noncoherent receiver circuits which timing (...)
Dear friends, I modified the following matlab code for QPSK to use it in frequency offset analysis code ==== %N=100000; % number of bits N = 2*100000; F_offset =; % multiple frequency offset values for x= 1 :length(F_offset) % frequency (...)
Dear Friends, what the relationship of frequency offset in simple BPSK system and OFDM-BPSK system? (how can i evaluate frequency offset for both system) are both have the same effect. if i have BPSK system sensitive to 25Hz for sampling frequency =1MHz , then OFDM with BPSK will have the same value (...)
I have a radio transmitting at 903.5 MHz and a receiver with a PLL fixed at that frequency. When i observe the signal after the mixer I see a frequency offset of 3.75KHz. What parameters of the PLL should I optimize to remove this offset?
What does it mean by carrier frequency in drives ? Why to lower carrier frequency ? YASKAWA AC Drive H1000 Super Heavy Duty, High Performance Drive Technical Manual Type: CIMR-HB ......... Models: 200 V Class: 0.4 to 110 kW 400 V Class: 0.4 to 560 kW MANUAL NO. SIEP C710616 37B The images are attached (...)
hello, I had decoded the rc5 protocol, i am getting the toggle bit perfectly. now i want to calculate the carrier frequency whit first two start bits. how to calculate that carrier freq?
I have the option to set the following values ​​of my signal generator: carrier frequency, frequency deviation and LF Gen. (R&S SMB100) LF Gen is frequency of the modulation signal but why to I have to set 3 different frequencies? Isn't frequency deviation already defined as the (...)
I have some basic doubts in communication. I got this while I was reading about Optical Communication. It states that "The higher the carrier frequency, higher is the bandwidth of the system." How can you say that? Also It states that optical communication has higher bandwidth when compared to normal communication using RF. Plz h
Please let me know that if want to make IR transmitter the carrier frequency must be accurately 36,38,40 kHz or 36kHz to 40kHz and what is the effect of change of carrier frequency in transmit range. How the carrier frequency change the transmission range?
Hi Friends, I want to know briefly about frequency offset estimation and correction in ofdm system... could you please any one can help me ?? Thanks in advance..
Hello everyone, In the past I've made with an atmega32 an infrared decoder and emitter and it worked for some IR protocols (like NEC, Sony) but now I want to improve it to work for air conditioning devices. The decoder/emitter is working for some AC devices (I've tested on two types) but not on all devices. The decoder/encoder is meant to be lik
I am using ADF4107 IC for PLL frequency Synthesizer in 4-5 GHz range. PFD frequency is 100kHz and Reference Crystal is 10 MHz. The PLL is locking. and the R-divider and N--divider values are appearing as expected but there is a fixed frequency offset appearing in the output , what could be the possible reason ,it is (...)
How is bit-rate related with carrier frequency ? Does higher carrier frequency always means high bit rate?This is how i understand it : If one bit is represented by a single carrier cycle,then obviously a 2Hz(just an assumption) carrier will take half the time in representing it than a 1Hz (...)
Dear friends I want references in different techniques used in "OFDM frequency offset Estimation and correction ". Also i need a guide to stat writing these techniques with Matlab codes
Hi, Does anyone has good tutorials about frequency offset estimation in GMSK ? Thanks