Questions tagged [synchronization]
The synchronization tag has no usage guidance.
111
questions
0
votes
1
answer
270
views
Loop Bandwidth for Carrier Demodulation loop
I am trying to implement a simple MATLAB model for the demodulators for phase modulated signals (PSK) used in communication systems.
For the detection of the phase modulated output (PM out in the ...
1
vote
1
answer
796
views
PLL for Phase Demodulation and Carrier Tracking
I've been playing around with using a PLL for phase demodulation and it's working pretty well. The PLL locks to the carrier and the error term is the demodulated message signal. However, depending on ...
0
votes
3
answers
522
views
Blind Carrier Synchronization
From my reading, I see that there are two ways people usually do carrier synchronization:
Decision directed, where the transmitted symbols are unknown are the receiver, decisions are made, and then ...
3
votes
1
answer
1k
views
Designing a PI filter for a Costas Loop
I am currently trying to implement a Costas Loop in order to demodulate a BPSK signal. Here is the reference block diagram I have been using to design the loop:Costas Loop Block Diagram
I originally ...
1
vote
1
answer
1k
views
How to allign audio signals after DTW?
Hello I am not a domain expert in signal processing but I need to align two audio signals.
I have seen the following page
https://librosa.github.io/librosa_gallery/auto_examples/plot_music_sync
I ...
1
vote
1
answer
174
views
NDA timing estimation for mutli-level QAM(RC pulse)
What non-data0aided techniques are used to estimate the timing for multi-level QAM? For single level QAM(so 4 QAM) you can use variance minimization or power maximization but I'm not sure these ...
3
votes
1
answer
69
views
Synchronising audio in realtime without knowledge of original signal
Was doubting whether this is the right SE forum to ask my (elaborate) question, so don’t hesitate to let me know if it’s not. Also, if anyone knows of a better way to title the question, feel free to ...
0
votes
1
answer
306
views
Initial Clock synchronization between multiple smart phones (android OS) connected over Wifi?
I want to synchronize the initial clock of multiple smartphone devices (Android-based) for real-time VoIP communication. Basically, a MANET has been formed and I want to synchronize the clocks up to <...
1
vote
2
answers
327
views
Digital PLL loses lock every time mesage crosses zero
I think my digital PLL is almost ready, but I've encountered this problem and I don't know what might be causing it, so I'd appreciate if you could help.
I'm using the DPLL in a Costas loop. It seems ...
0
votes
1
answer
94
views
How to synchronize audio and video streaming for not fixed FPS streaming?
It's a 3-stage process.
In the first stage, a video (with audio) is recorded at a fixed 25 FPS rate. In the second stage, it's demuxed in two different channels and the video is processed. In the ...
0
votes
1
answer
54
views
Need some references on sound quality evaluation and syncing
I have to do a project where I'm receiving the same sound signal from different channels (with different offsets), but they may not be consistent all the time. At any given time, I should decide which ...
5
votes
1
answer
1k
views
Maximum cross-correlation coefficient value for time delay estimation
I am using cross-correlation for time delay estimation of two synchronized recordings ($x_1$ and $x_2$) of a fixed sound source from two different locations.
I understand that the delay is associated ...
0
votes
0
answers
689
views
How is DJI OcuSync wireless link physical layer implemented?
I'm looking for documentation on the wireless command link of the DJI OcuSync. I found this website (in Chinese). It seems like an OFDM link that uses Alamouti codes?
I'm specifically interested in ...
0
votes
1
answer
96
views
Synchronization Accuracy Required For Communications
One of the biggest problems in phase modulated communication is discovering when your signal has arrived. High accuracy in this area is important, as even a quarter wavelength error can cause the ...
0
votes
1
answer
159
views
QPSK demodulation problem due to apparent transmitter clock frequency drift
I am using FPGA to generate 10Mbaud QPSK signal in two channels corresponding to two quadratures. Upsampling to 1GSample/s (using raised cos filter for interpolation) and complex upconversion (f_up=...
3
votes
1
answer
1k
views
GNU Radio loop bandwidth normalization
From GNU Radio documentation, the control_loop block proposes loop bandwidth values in the range $[\frac{2\pi}{200}, \frac{2\pi}{100}]$ in radians per sample.
Some blocks, like the new timing symbol ...
0
votes
1
answer
176
views
Synchronize a software waveform generator
I'm having some trouble with a software waveform generator I'm attempting to put together. Especially with synchronizing the waveform.
Goal
Generate a mains synchronized (50 Hz) sinusoidal waveform ...
1
vote
1
answer
727
views
Frequency Hopping Spread Spectrum Synchronization Methods
Frequency-hopping spread spectrum waveforms change the carrier frequency at some interval.
I can see if the frequency is constant for the duration of an entire packet, the pilot symbols could be used ...
1
vote
1
answer
786
views
OFDM: How to do the carrier recovery of the quadrature(I/Q) demodulation
For an OFDM system, after the OFDM modulation, the quadrature modulation is used to move the signal from the baseband to the pass-band.
But when it comes to the receivers, I can't find any way to make ...
1
vote
0
answers
308
views
Band-edge filtering for an RRC pulse-shaped manchester/biphase-encoded bitstream
Band-edge (derivative matched) filters can be used to generate an error signal for frequency locked loops (real part) or symbol timing loops (imaginary part). The derivation of the band-edge filters ...
2
votes
2
answers
1k
views
Timing recovery in GNU Radio : Variable rate vs Fixed rate operation
I have been wondering about the implementation of timing recovery blocks in gnuradio. In literature, for asynchronous sampling, all that is needed are error detector (MM, ML, Gardner etc), a loop ...
0
votes
2
answers
3k
views
Trouble with time-syncing two radio signals using cross-correlation
I posted a similar question a while ago here (I'm posting this follow-up since I'd like to focus more on cross-correlation now). I have a setup where I have two software-defined radios connected to ...
3
votes
0
answers
248
views
Synchronization of BPSK with variable-length symbols (ISO 14443)
Does anyone have an idea how one would perform BPSK symbol synchronization if symbol length is allowed to vary?
As dumb as that sounds, this is not a theretical question.The "Proximity" Type B NFC ...
0
votes
2
answers
151
views
Synchronization with a specified sequence
I'm currently creating a project in Matlab where I'm simulating a communication, based on the SSB modulation, between a transmitter and a receiver.
I've added a Barker sequence in the trasmitted ...
2
votes
2
answers
924
views
How can I synchronize signal from an LED and TTL pulses better?
I would like to synchronize my video and voltage data using Python. (I obtain these data using Bonsai and Open Ephys for an open field exploration experiment.)
I sent $150\text{ ms}$ long TTL pulses ...
1
vote
0
answers
35
views
How does the M-law Synchronizer work?
Relatively new to DSP, I've came across the approach for phase-estimation of PSK-Signals x(k):
My question is:
What do we get by exponentiating the Baseband-Signal?
4
votes
1
answer
733
views
FFT based symbol synchronization for digital demodulation
Where can I read more about "slow search" methods for symbol synchronization based on FFT for extracting a clock signal from the modulated signal?
I have read here (8.7 Symbol synchronization)
One ...
1
vote
0
answers
492
views
Frequency Domain Variant of Pearson's Sample Correlation Coefficient?
Suppose that you need to find (i.e. acquire) $x_1$, a short data packet with a known bit sequence preamble (i.e. a PRBS BPSK), in $x_2$, quantized samples recorded from the output of an ADC. You don'...
1
vote
1
answer
495
views
OFDM synchronization using training symbols
In OFDM receivers, special OFDM training symbols for which the data content is known, can be used to perform the synchronization process. A correlation operation is performed between the received ...
2
votes
0
answers
86
views
Detection over AWGN analysis disagrees with Monte Carlo simulation
I have a fixed vector $\mathbf{s} \in \{\pm1\}^m$ and a random vector $\mathbf{d} \in \{\pm1\}^m$.
I send either $\mathbf{x} = \mathbf{x_1} = [\mathbf{s}\space\mathbf{d}]$ or $\mathbf{x} = \mathbf{...
-1
votes
1
answer
815
views
Synchronizing 2 seperate speech audio signals
I have two speech signals: one with a man reading a passage, and one with a woman reading the same passage.
I want to synchronize these signals so that, for each word, their readings line up. The ...
2
votes
0
answers
490
views
Software based synchronizing of multiple data streams/sensors with slightly differing sampling rates
Situation:
I try to synchronize the data streams of multiple sensors (ADXL372) of the same type but with different data output rates. The data sheet states all sensors should have the same sampling ...
0
votes
1
answer
1k
views
Measure the amount of drift in video and audio frames
I setup a stereo system using 2 GoPro Hero Session Cameras, since I need a larger baseline than the one of the Dual Hero System.
This unfortunately means the two cameras are not ...
3
votes
0
answers
2k
views
Synchronizing signals with different sample rates
I am relatively new to signal processing, so I am still missing some basic knowledge, but I am trying to improve as much as I can. I am trying to synchronize two signals with matlab using cross-...
2
votes
1
answer
593
views
Band edge filter for raised cosine impulse
I'm hoping to use an implementation of a frequency-locked loop for rough frequency synchronization in a PSK31 demodulator. The approach is to define a filter that is the derivative of the matched ...
0
votes
1
answer
2k
views
Acceptable Carrier Frequency Offset for Specific BPSK system
I've been working to build a transceiver system, with details as follow:
Consists of Lime LMS6002D MyriadRF-1 board (RF front-end) and own-designed multi-proc SoC (baseband processor).
SoC is running ...
1
vote
1
answer
170
views
Is Spectral Coherence (MSC) dependent to the initial amplitude of the comparing signals?
Given the signals
\begin{align}
x(t) &= A_1\sin(\omega t)\\
y(t) &= A_2\sin(\omega t)
\end{align}
Do $A_1$ and $A_2$ play a role in the $C_{xy}$ coherence estimator? MATLAB's ...
3
votes
3
answers
418
views
Sampling and Reconstructing Digital Signal
Say that I have a digital signal (a bitstream actually) whose output changes every 100 mS. I don't know exactly when it changes relative to my sampling, only that that the next bit to capture appears ...
1
vote
0
answers
568
views
How can I perform timing recovery from the envelope of PSK signals?
I'm trying to reimplement FDMDV in GNU Radio, largely for educational purposes. It consists of 15 PSK subcarriers, 75 Hz apart, 50 symbols/sec each. The center one is BPSK and alternates phase each ...
3
votes
1
answer
285
views
Why does signaling overhead for time synchronization scale up with the number of transmitter nodes in a multiple access system?
I was recently reading about random multiple access methods without time synchronisation (of the pure Aloha type). In this paper it is stated that,
The need for transmitter synchronization is a ...
0
votes
1
answer
478
views
How to find a know signal in another signal which contains other signals along with the signal i need in python
I am working on BPSK with sound waves a carrier waves.
Actually I am modulating my data with some known sync bits along with the information I need to send. So the things I will be having at ...
1
vote
1
answer
134
views
How to find the time instant where my sent signal and received signal can synchronize?
I am having two .wav files, one is modulated wave that is made into a .wav file and another is a recieved .wav file which is recorded from microphone while playing first modulated .wav file. So now ...
3
votes
1
answer
521
views
Symbol timing recovery design
I am trying to design the Symbol timing recovery(#STR) block of #DVBS Receiver. These are the specifications
Symbol rate ($f_s$) = $2\textrm{ MHz}$
Acquisition range = $10\%$ of Symbol rate
...
3
votes
1
answer
2k
views
Loop bandwidth for symbol timing recovery
I am trying to design the Symbol timing recovery (STR) block of DVBS Receiver.
How should I chose the loop bandwidth and damping ratio for determining the loop filter coefficients $k_1$ and $k_2$?
...
2
votes
3
answers
1k
views
Synchronization of two audio tracks via Mel-frequency cepstral coefficients (MFCCs)
I am trying to solve the (common) problem of synchronizing (i.e. measuring the delay between) two audio tracks recorded from different sources during a conference talk (about 1h of audio). One track ...
2
votes
2
answers
5k
views
What are the advantages of barker sequence over marker sequnce?
I read that barker sequence is used for synchronization among other uses. Barker sequences are rare and they have special properties - this part I understood. I am missing some thing when I think ...
0
votes
2
answers
4k
views
OFDM symbol acquisition block in GNU Radio gives rotating constellation even if there is no carrier offset. How is this possible?
Why does the constellation rotate when using OFDM Symbol Acquisition block in this flow graph below ?
The only explanation I could think of would be carrier frequency offset but in this flowgraph ...
0
votes
3
answers
6k
views
Phase locking value / phase synchronization
I have pairs of EEG signals filtered to give me just alpha bands. For a machine learning problem I have found that calculating the phase locking value between the alpha signals of these 2 channels ...
0
votes
0
answers
107
views
"Time To Lock" in Bit Timing Synchronisation
In the context of bit timing synchronisation in digital communications, what is meant by the requirement that says the "Time to lock to a sampling point should be no more than X symbols"?
There seems ...
0
votes
0
answers
3k
views
How to compute transfer function (Frequency Response Function) from experimental data
I have a set of data, in the freqeuncy domain, corresponding to a structural test.
I have amplitude, phase and frequency for both the measured output and the input signal (accelerations are measured ...