Questions tagged [gnuradio]
GNU Radio is a free software development toolkit that provides the signal processing runtime and processing blocks to implement software radios.
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Find the SNR of an FM broadcast signal in GNU Radio?
Any ideas on how to find the SNR of an FM broadcast signal in GNU Radio? I have seen an SNR estimator block for MPSK modulation? Do I need to create an OOT block for calculating SNR of FM signals or ...
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19 views
QPSK signal 'passthrough' - not working as expected
as a fun project I am trying to build Quadrature Phase Shift Keying (QPSK) modulator & demodulator for a Digital Video Broadcasting (DVB) application. I am using the LimeSDR mini as my hardware ...
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52 views
GNU Radio | Transceiver loopback adapted | Transmission stops unexpectedly
(This is a follow up question to a previous question: link)
I have implemented a flowgraph of a transceiver loopback inspired by the examples found at ...
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46 views
GNU Radio | Async FEC encoder/decoder loopback | Issue during decoding?
I have implemented a loopback flowgraph intending to perform the following:
FEC encode (repetition code) an input stream in16_2.dat
Store the encoded stream as <...
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22 views
Any ideas on creating a GNU radio block for scanning active frequencies (FM/AM/DAB/DVB-T)?
I am trying to create a GNU Radio block that scans the active frequencies, let's say for FM/DAB channel. I have seen scanner implementations in c++/python but are not compatible with GNU Radio. Can ...
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1answer
68 views
GNU Radio | Packet Encoder/Decoder | Unwanted bytes added to the transmitted stream
(A follow up question can be found here: link)
In an attempt to understand how the packet encoding blocks work I tried to mimic the experiment performed by Aaron, published in this post, but reduced ...
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23 views
Changes in amplitude after Quadrature Demodulation
I'm getting the FSK signal from the satellite in I/Q format (see the last 2 waves at the bottom of the picture).
After applying Quadrature Demodulation, I'm getting the top wave.
The questions are:...
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1answer
63 views
GnuRadio's SNR estimators usage
I'm trying to calculate the SNR of a satellite signal using GRC, but all of the 4 offered estimators either have a lot of -NaN values or are ~35dB throughout the entire recording.
(I just connected ...
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1answer
38 views
Channeling two named PIPEs with a GNU Radio flowgraph | String transmitted on one end does not reach the other end
1)
I created two named PIPEs:
$ mkfifo pipe_in
$ mkfifo pipe_out
2)
Then connected pipe_in to ...
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49 views
Working principal of MIMO(2 by 2)-OFDM (802.11n)
I have gained basic knowledge on MIMO-OFDM from online sources and in process of building 802.11n standard in GnuRadio+USRP B210. My goal is to analyze the channel state information and play with it ...
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26 views
Creating GNU radio flowgraph for continuous switching between transfer and receive mode
I am having a hackrf-one device which can either transmit or receive signals. I am having a GNU radio flowchart which has a selector block which allows manual switching.
I am not able to switch it at ...
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1answer
80 views
Can a software defined radio with a frequency range of 300 MHz – 3.8 GHz detect AM (535 to 1705 KHz) and FM signals (88 to 108 MHz)?
I am interested in knowing whether BladeRF SDR with a frequency range of (300 MHz - 3.8 GHz) detect AM and FM frequencies? Also, how important is the sampling rate of the SDR. For example, BladeRF has ...
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1answer
134 views
Residual carrier tracking with PLL
Residual carrier systems such as PCM/PM/NRZ and PCM/PM/Bi-phase are common in space applications. Compared to suppressed-carrier systems such as BPSK, the literature sources on residual-carrier ...
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146 views
EbNo, SNR, and BER simulation for BPSK with convolutional code
Im currently simulating BER performance of CCSDS convolutional code. Im having some troubles in specifying EbNo and SNR in gnuradio blocks.
From matlab webpages on BER simulation for RRC pulse and ...
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45 views
How can I tune into two FM frequencies at the same time?
I have a file source for a FM radio capture and have a working FM tuner. I need to tune into two frequencies and listen at the same time.
Any help to accomplish this would be appreciated!
Current ...
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68 views
Phase noise modeling using gnuradio IIR filter
I need some advice regarding phase noise modeling using gnuradio IIR filter. I'm trying to synthesize phase noise (multiplicative) with a given noise mask. In one paper, the authors were able to ...
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29 views
Group delay emulation in GNU Radio
I'm trying to test an equalizer against group delay distortion of a satellite communication link. According to the CCSDS standards, It is agreed to simulate high-order modulation system with in-band ...
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1answer
142 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 ...
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31 views
“Image Processing” [closed]
I'm an Italian student. I'm studying Gnu Radio and I would like to upload a photo, can I upload it with "file image source" or other blocks?
I need to make FFT of an a image. -> image 2D
Thank you ...
2
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1answer
78 views
Recovering data from mystery signal
I was scanning the airwaves using my RTL-SDR and found a signal being broadcast locally that I was able to receive. When I configure the SDR Console V3 software to NFM, I get the following audio. (Wav ...
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1answer
253 views
Why am I seeing a negative frequency on FFT graph in Gnu Radio Companion? [closed]
I have a pretty simple flow here in GRC, but for some reason I'm seeing a negative frequency mirroring the 10khz signal that I'm generating. What's causing this negative frequency to show up in the ...
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1answer
139 views
am I recording LTE uplink signals?
I have this app in my phone which tells me the LTE UL frequency and power:
so I went with my SDR and measured the received signal at that frequency:
Now, how can I be sure this is the transmitted ...
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98 views
Dynamic loop bandwidth for a Costas loop
I'm using a Costas loop for carrier recovery. The BER vs SNR (from GNU Radio Simulation) curve for different loop bandwidths (0.03,0.05 and 0.07) is shown in the graph below. It can be seen that the ...
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1answer
94 views
Emulating a Variable Delay
I am trying to emulate a satellite link where the delay time between the satellite and ground station changes over time due to the satellite's motion. I plan do this by converting to the frequency ...
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0answers
61 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 ...
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129 views
Blind equalization with constant modulus algorithm in GNU Radio
I'm currently simulating the effect of multitap channel on BPSK as well as its remedy i.e. equalization.
The modem is expected to work with satellite TT&C transponder.
The communication channel ...
2
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1answer
680 views
Pulse shaping with RRC : Number of taps
I am running a BPSK flowgraph in GNU Radio which is based on RRC pulse shape. I noticed that the BER is quite poor when the number of taps is low. However, using the number of taps around $20\times ...
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1answer
47 views
Analog equivalent for transition width in Digital radios
I have started off with GNUradio and I am not sure if I understand the transition width parameter available in GNU radio companion filter blocks .
As per online documentation transition width of a ...
2
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1answer
273 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 ...
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209 views
GMSK/GFSK BER simulation in GNU Radio : How to specify signal energy
In GNU Radio, BER vs SNR can be measured by fixing the signal energy and varying the amplitude of the noise source block. For example, in BPSK, we have transmitted signal $s\left(t\right)$ with a ...
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0answers
311 views
Carrier recovery with the Costas loop : PLL pull-in range
I have created a channel model in GNU Radio (a modified version of the default GNU Radio Channel Block). Its performance under AWGN (without timing, phase or frequency offsets) aligns properly with ...
2
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1answer
418 views
PLL phase and frequency characteristics
I'm currently working with BPSK carrier phase and frequency recovery in GNU Radio. I have been able to use Costas loop and Frequency locked loop (four carrier acquisition) which are based on the ...
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1answer
194 views
BER vs SNR simulation for GFSK modulation (Closed-form BER for GFSK)
I'm in the process of simulating the performance of a GFSK modem in GNU Radio. I have managed to get a curve similar to the curves I see in a number of literature sources. However, I need an accurate ...
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2answers
638 views
GNU Radio QPSK 4 Symbols
I'd like to generate a simple QPSK signal in GNU radio, but so far I haven't been able to get it to perform the way I'd like and I'm not sure if this has to do with some misunderstanding I have about ...
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66 views
Satellite receiver suite
I'm in the process of implementing a general purpose baseband system for modulation schemes (Linear + CPM) commonly used satellite and deep-space TT&C as shown in the functional flow block diagram ...
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287 views
Software Defined Radio samples analysis using gnuradio and python
I'm trying to replicate what gnuradio is doing in "pure" python with a hackrf. Having mixed result, I decided to use the same data to compare the outputs I obtain. My gnuradio workflow is the ...
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1answer
187 views
AM demodulation from a real RF signal
I'm capturing an RF signal transmitted at 433.8MHz, with a bandwidth of about 50KHz. My goal is to be able to save it as a .wav file.
I'm using an RTL-SDR dongle and a software named HDSDR, where I ...
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0answers
990 views
USRP + GNU Radio as 1 GHz bandwidth spectrum analyzer
I have maybe not trivial but some interesting question.
I need to create 802.11ac channels spectrum analyzer with USRP.
Hardware: USRP B210
Software: GNU Radio 3.7.9
PC: Intel Core i3 i3210m 16 GB ...
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2answers
2k views
How does transition width of a low-pass filter affect a message which is well within the pass-band?
I'm taking a communication systems course and we use GNURadio in the lab. In an exam, we had a simple question where we were asked to demodulate a Dual Side Band (with carrier) AM signal in GNURadio. ...
3
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0answers
632 views
gnuradio: How can I change the value of the tag exiting the “Correlate Access Code - Tag” block?
Background: I have built a conventional demodulator in gnuradio and am trying to send payload data out of the flowgraph to an external Python script. I'm using gnuradio v3.7.12.
It seems to me that ...
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0answers
339 views
GNURadio Sending Short Packets
I'm trying to create a basic GNURadio flow graph that will transmit a short message in order to receive an appropriate reply back.
I currently have the following flowgraph:
I have a program that ...
2
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1answer
3k views
How do I extract data from a gnuradio flowgraph now that the message sinks have been deprecated?
Background: I am writing a Python script that contains a gnuradio flowgraph object used to demodulate incoming IQ data. The flowgraph is started and runs while I periodically poll it for demodulated ...
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1answer
105 views
Better way to mute fundamental baseband frequency?
I'm working on a project to monitor the fluctuations and harmonics present on standard 120VAC mains power. I built an adapter that drops the voltage from 120VAC to 12V and then down to 0.5-0.6 VAC ...
9
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1answer
478 views
What kind of modulation is this?
I'm trying to find out what kind of modulation and encoding is used by my window cover remote control, aiming to implement the same on a Raspberry Pi to add a bit of home automation.
A colleague ...
3
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1answer
720 views
Avoiding DC spike while decoding FSK signal
I am using the Quadrature Demod module in GNU Radio to decode an FSK signal, but the signal is appearing quite noisy. It has two distinct peaks centered around the advertised frequency, but they are ...
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2answers
497 views
Use GNU Radio to extract information from a VOR signal
I want to design a GNU Radio project to extract the information of a VOR signal, then find the angle to the north and the Morse code of the station.
Is there any example that shows how to do it?
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198 views
how can i use gr-specest in gnuradio? [closed]
hello Pr how can i use the fam and the gr-specest in the GRC for cyclostationary features
------------------------------------------------------------------------
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0answers
167 views
Unable to stabilize 8-PSK signal with self designed costas loop
I am trying to make a signal processing block which implements the costas loop to stabilize an 8-PSK signal. Here is the flowgraph with "costas_loop" being my block.
My workflow is the following -
<...
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0answers
372 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
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1answer
97 views
Frequency components much less prominent at the receiver for multiple tones
I am trying to transmit a multi-tone signal from one USRP (N210) to another and have written an out of tree block to generate the multi tone signals using an ifft. The two USRPs are connected directly ...
