Questions tagged [synchronization]
The synchronization tag has no usage guidance.
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Sampling frequency in digital communication with higher order modulation (QPSK, APSK)
Is it necessary to use a sampling frequency higher than the Nyquist frequency in digital communication?
In general, it is known that to receive a signal with bandwidth $B$ the sampling frequency equal ...
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Synchronize to coded signal for detection
Forgive my ignorance of terminology.
I've achieved synchronous demodulation (lock-in amplification) of an optically transmitted code a few years back, i.e. transmit and integrate whatever gets picked ...
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What is the best way to sync I/O audio streams to mix them in real-time?
I want to mix loopback stream with audio from microphone in real-time and use the result of mixing for speech recognition.
The project is for Windows, so I use WASAPI and am willing to know what is ...
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How to sync two similar lists/waveforms with differently populated data in python?
I have two lists of sizes L1 - 22400(865*26) and L2 - 79000 with measurements of some environmental data. Data of both the lists are measured simultaneously. The L2 is a continuous measurement for ...
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Interpolation Control for doing Timing Recovery in FPGAs
I intend to make a timing recovery circuit on an FPGA and for that I have to make synthesizable models of Xilinx Blocks for Interpolation Control (Module-1 Counter based)
in Simulink.
I have made ...
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Why do I have to increase the delay periodically while trying to synchronize two streams at the receiver?
I am trying to synchronize two streams at the receiver in GNU Radio.
You can see in the Picture below that I subtract the receiver signal from the signal that has been demodulated and modulated again. ...
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How can a costas loop work when root raised cosine filter used on QPSK signal?
I just finished a costas loop for QPSK signal,I transmit the baseband signal and sent it into the costas loop, which worked well, but when I filter the baseband signal with root raised cosine filter ...
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Issue with small signal ML TED with low RRC excess bandwidth
I have a simple BPSK system using RRC TX & RX filters with 10% excess bandwidth with a receiver that uses a symbol synchronizer of the common type consisting of a polyphase filter bank (performing ...
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Understanding the (complex) GNU Radio implementation of Mueller & Muller
I have some questions about the M&M implementation of GNU Radio that uses complex samples.
I started reading the implementation for real values:
...
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Sliding Window correlation vs cosine of relative phase
I create two band limited signals having a specific time-varying covariance at each time point using cholesky decomposition. My aim for this experiment was to show a scenario where sliding window ...
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Can PLL for OQPSK be used for carrier frequency recovery?
This is the phase detector of PLL of OQPSK modulation. Apparently, it introduces a self-noise labeled in red which can’t be offset. I simulate this algorithm in Matlab, it doesn’t perform as well as ...
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Symbol Sync blocks in GNU Radio seem to use PID (well, PI) for their clock sync feedback loops. Why not IIR/FIR?
E.g. the Symbol Sync block has a Loop Bandwidth, which (if I read the source right) ends up as a PI loop.
I know what PID does mathematically, and what FIR and IIR ...
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The MSE after each synchronization block doesn't go consistently down at the output of each block
I have a synchronization chain that consists of
Coarse frequency synchronization block
Frame synchronization block
Symbol time synchronization block
Fine frequency synchronization block
PLL phase ...
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217
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CFO limit for correct LTE Zadoff-Chu Synchronization
I am working with Zadoff-Chu sequences in a Python simulation of an LTE-like communication system and need to understand the effects of carrier frequency offset (CFO) on these sequences. Specifically, ...
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Synchronization blocks and the domain in which they operate
I'm studying the full synchronization chain, and it's not clear to me at which domain each block works on in terms of sample vs. symbol domain. I'm particularly confused between frame synchronization ...
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Probability of miss detection and probability of false alarm in frame synchronization
I'm working on frame synchronization, and I don't fully understand the probability of miss detection and probability of false alarm in evaluating the performance of the synchronization block. As far ...
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Need to write a simple code in matlab of training sequence or zadoff Chu sequence for my OFDM signal-synchronization
I have written a complete code, in matlab, for my ofdm signal for the transmitter and receiver. Now I want to transmit my ofdm signal via wireless channel using SDR.
Now, I need to combine a simple ...
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Is there any specific order for the synchronization blocks at the receiver?
I am working on frequency, time and phase synchronization at the receiver, and although there is a consensus that coarse frequency synchronization is the first block in the chain, I am confused about ...
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What is the name of this FFT technique for carrier recovery?
https://dsp.stackexchange.com/a/67221/69442
What is the name of this FFT-based technique whose code is given in the answer and whose link I added above? Can I find information about this in any paper?
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QPSK demodulation carrier frequency offset compensation on python
I am new to signal processing and I am trying to demodulate the IQ data, and I am stuck on the carrier frequency offset compensation.
I has 1000 samples and it is 1MHz data.
For the general idea, I ...
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What's the difference between frequency shift, frequency offset, phase offset, and phase noise?
I'm confused about these terms: frequency shift, frequency offset, phase offset, and phase noise. My understanding that frequency shift and frequency offset are the same and caused by Doppler shift. ...
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Symbol synchronization interpolation control
Could anyone explain the action of interpolation control in symbol synchronization? What the underflows mean? And how it provides the fractional part? I know how other components work but don’t ...
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Find out time offset between two substantially same audio tracks
Say we have two audio tracks of the same movie but from different sources. The length of the animated logos at the beginning is different, so the actual movie audio starts slightly earlier on one ...
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Sampling Time Offset estimation for OFDM signal
I have a signal constituted by known OFDM symbols, and my goal is precisely estimate the Sampling Time Offset (STO). However, while the STO in the context of a single-carrier modulation is pretty ...
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Why are preambles repeated in communication systems
Many modern digital communication systems repeat a preamble at the start of a frame/burst which is used by the receiver for timing and frequency synchronization. One example is 802.11a. Why are the ...
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Synchronizing two sets of data sampled at different frequencies
I have two different datasets.
Dataset 1 has a frequency of 1000Hz/sec and dataset 2 has a frequency of 50Hz/sec, how can I synchronize the two datasets so that they can be used as training data?
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215
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oQPSK symbol synchronization
I'm validating a C++ oQPSK receiver. The 5Mbps oQPSK signal is generated by a satellite emulator. The receiver structure goes as follows:
SDR --> AGC --> Costa's Loop --> Delay --> ...
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Is there any sampling offset when using external reference signal
I perform real experimental tests for optical communications using DCO-OFDM. The transmitted signal is uploaded into an AWG (arbitrary waveform generator), then bias (2.5 V) is added before adopting ...
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Why should costas loop be done after clock recovery, as opposed to before?
In GNURadio's PSK tutorial they place the costas loop after clock sync and linear equalizer. This seems odd to me.
I'm thinking that it's easier to lock onto a carrier frequency at the higher RF ...
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Problems with PSS phase offset calculation algorithm
I'm trying to implement a carrier frequency offset (CFO) estimation algorithm to correct my phase offset with the correlated PSS signal.
The algorithm for a corelated signal y(n) is as follows:
y(n) ...
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synchronization algorithm for cpfsk modulation
I am searching for simple and efficient algorithm to implement in order to estimate the symbol timing offset for synchronization purpose
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SDRs synchronization
I have 3 software defined radios (we can suppose that we have Ettus X310). I need to synchronize them because I need a high level of accuracy.
I know that I can use the Octoclock to synchronize them, ...
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Synchronization for busty signals by correlation methods
I'm trying to reuse standard synchronization algorithms for phase(Costas) and Time (Polyphase Filter bank) for receiving bursty signals. The bursty signals are transmitted every 5 seconds. The signals ...
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Synchronizing 2 time series signals at slightly different sampling frequencies
I'm working with an embedded system that has two acquisition channels and unfortunately, their clock crystals are slightly out of sync. Even though both boards are configured by software to sample at ...
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Derivation of Costas Loop SNR in digital domain
The tracking performance of PLL-based is often expressed in terms of error variance. To take into account the effect of Loop bandwidth, another parameter, called loop SNR is used. Loop SNR for an ...
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333
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Costas Loop SNR
I've seen in literature that loop performance is inversely proportional to loop SNR. The higher the loop SNR, the lower the variance, the better the performance. My question is how do we calculate the ...
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Frame synchronization for single carrier burst applications in fading channels
I recently started to implement communication systems with software-defined radios in GNU Radio. In my system design, I am planning to transmit data in burst mode, the frames will be not sequentially ...
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How can I fix bad clock recovery for bursts with short distance?
I use GNURadio as a prototyping tool to build a receiver for a digital signal of a home appliance. The signal itself looks good so far.
Also the symbol synchronization works well using the symbol ...
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Confused about the difference between frequency synchronization and phase synchronization
I am not sure if this is the correct place to ask this question but it looked like the most fitting SE site.
I study software engineering and I am taking a course about networking, where ...
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In OFDM, does the parameter time offset is important if there is only one mobile in the cell?
I am learning about OFDM, and in my reading, I have noticed that (mentioned everywhere) synchronization is a very critical aspect of OFDM. Here, I am writing in the context of time synchronization (...
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Why is phase range between $-\pi$ and $+\pi$ (instead of $0$ and $2\pi$)?
I wonder why the phase range in DSP applications is between $-\pi$ and $+\pi$.
For example, why is that not between $0$ and $2\pi$?
This question popped when I was reading about synchronization in ...
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Design a timing recovery algorithm with predefined samples with max amplitude
I need your help in understanding how to simulate a timing recovery algorithm. I have already read a lot of literature and posted here the question but I have still doubts how it works.
Let me briefly ...
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Band-edge timing error detector, time accumulator
im trying to implement a band-edge FLL and timing locked loop from this paper (https://www.researchgate.net/publication/261499267_Band_edge_filters_perform_non_data-...
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Correcting large frequency offsets at very low data rates
Consider a typical BPSK system running at a baud rate of 1 kbaud/sec - the receiver needs to deal with severe frequency offsets, let's say up to +/- 1 MHz offset and that the frequency offset can ...
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Symbol time offset simulation
I ran a number of simulations for symbol timing synchronization in the past. I used GNU Radio mainly. Now, I'm trying to do the same thing in C++. To achieve that, I need a way to introduce symbol ...
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Dealing with bias in an FFT for frequency correction
I'm working on using an FFT for frequency correction of a generic modulation signal. My algorithm basically attempts to balance the energy in the positive and negative frequencies of the FFT to be ...
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Actual Sample Rate slightly off?
When capturing microphone audio, I noticed that my static buffer eventually overflows.
So I timed the samples, and low and behold I'm getting an actual sample rate of 44102-ish Hz (my timer is very ...
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Synchronization of tx and rx in sdr
I am implementing a FMCW radar using bladerf sdr:
When reading the output from the vector sinks, the outputs are not synchronised.How should I synchronise them? is it possible to do so using gnuradio ...
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aperiodic auto correlation properties
I'm reading about PSC (primary synchronization code) in UMTS. It is a so-called Golay sequence.
It is said it has a good aperiodic auto correlation properties.
What does it mean (in terms of aperiodic)...
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Symbol synchronization with unknown symbol rate
I'm learning about the early late gate symbol synchronization and understand that it needs to be given the symbol rate ahead of time.
How could a multi-symbol rate system use an early late gate?
It is ...
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