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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GNU Radio Companion - Constellation Modulator - what is the reason behind the interesting Time Sink waveforms obtained?
For my setup of a Constellation Modulator block and QT GUI Time Sink block, with the symbol map for the Constellation Object being [0, 1, 2, 3], and the Constellation Points for the Constellation ...
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4 views
Doubt about sampling rate and spectrum with USRP and gnuradio [duplicate]
I have started working recently with software defined radio (SDR) as well as gnuradio. I have worked with digital signal processing for a while and one feature at one tutorial, which I saw for ...
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42 views
GNU Radio Companion - Constellation Modulator block - how to generate single constellation point only?
I'm beginning to learn about the Constellation Modulator block, and just trying it out by setting up a 4-QAM system, with the constellation points arbitrarily set as : [-1-1j, 1-1j, 1+1j, -1+1j]
And ...
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1answer
159 views
GNU Radio Companion - generating a 4-QAM constellation - how to do it?
I'm doing the baby steps right now to learn about GNU Radio Companion. I'm using 3.7.13.5 at the moment.
I'm just focusing on getting a simple binary stream together, such as '110100' (repeated) .... ...
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35 views
TypeError: primitive_connect() when executing in gnu radio
I'm building the frequency analyzer for RTL-SDR. But having problem in building and executing code.
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1answer
29 views
What is wrong with this GNURadio flow graph?
I am simply trying to modulate a wav file sampled at 22.05kHz, then demodulate it. The audio output is choppy and I get errors in the console output ("volk warning, no arch found... though I've ...
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1answer
24 views
Why does applying RRC to the signal increase bandwidth?
Please see this question: Why samples per symbols $\geq 2$ in the GNURadio Constellation Modulator block?. The first answer here says "filtering the signal, you have bandwidth expansion". ...
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45 views
Can I create my IF signal on SDR before bringing data to PC?
I'm relatively new to SDR's and I'm trying to determine what sort of BW I need for my laptop to get the best resolution possible for an FMCW system. I have an X310 Ettus with a UBX160 daughtercard ...
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1answer
18 views
gnuradio: Best way to sync to simple preamble
I never figured out a clean way to sync to a simple preamble in GNU Radio 3.7/3.8, so I built my own block to do so. It was a variation on the Correlate Access Code - Tag Stream block that simply cut ...
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1answer
17 views
Why I get another spectrum when upconvert an o-qpsk baseband signal with a bladerf compared to a hackrf device?
I have just start working with bladerf instead of former used hackrf hardware and I need to solve a problem. Currently I use the following bladerf hardware, libraries and firmware:
bladerf (2.0 micro ...
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21 views
Why do I see a frequency shift from center when transmitting a QPSK via USRP with GNU Radio?
I am transmitting a QPSK signal via GRC and when I look at it on the spectrum analyzer, the signal is shifted away from my center frequency. This shift increases the higher the center frequency (i.e. ...
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15 views
What modulation is done when I connect a signal source to a USRP block in GNURadio?
When I connect a sinusoidal signal source to a USRP sink and upconvert the frequency, what modulation is done to convert the baseband signal to a passband signal?
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93 views
QPSK demodulator on GNURadio continuously loses phase lock
I am designing a QPSK demodulator to be used for receiving Meteor M2 (LEO satellite) signals (QPSK at 72Kbaud). However, I am finding a lot of problems in my way.
First of all, this is the flowchart I ...
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34 views
Advice on generating stable FMCW waveform
I am trying to derive parameters for a triangular FMCW waveform such that the phase of the signal has consistency from one period to the next. Perhaps this is arbitrary and feel free to tell me so, ...
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1answer
42 views
Unstable frequency/phase when using external reference for Ettus B200
I am attempting to do a simple record of a CW, 250MHz signal at the Rx port of an Ettus B200 using an Anritsu MG369 signal generator. I am using the 10 MHz ref signal provided by the SG (output @ ~...
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25 views
Need to extract phase of incoming signal, how to find FFT bin of frequency of interest in GNU Radio?
When receiving a higher frequency signal, say 2 GHz, the freq as shown in frequency sink is often off by some amount (1-2 MHz) on the ettus B200. So I can't just assume the location of the signal is ...
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28 views
What is the successor to the GNURadio liveCD?
I used to burn and run the GNU Radio livecd - it was a very nice package that gave me a working gnuradio environment - with drivers and tools - without doing a lot of sysadmin or package management, ...
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27 views
Bit error rate transient
I see often people here posting about GNU Radio, I hope mine is not in the wrong place.
I try to implement a demodulation chain and would like to measure its performance.
I added a BER block and it ...
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1answer
55 views
Why samples per symbols $\geq 2$ in the GNURadio Constellation Modulator block?
Let's say I want to emulate the design of a modulator I am building "in real life". I'd like the components, input data rate, and output bandwidth to be the same as in the real system. If ...
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2answers
76 views
Why is the bandwidth for this QPSK system larger than expected?
Below is my gnuradio-companion graph.
As you can see the sample rate is 100k, I am modulating with QPSK, and am filtering the waveform (RRC) with the "Excess BW" parameter, at 0.35. The ...
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79 views
Offset QPSK Demodulation using GnuRadio
I am currently trying to demodulate an Offset QPSK signal coming from a satellite using GNURadio.
If I understood correctly, an OQPSK is a QPSK with one of the two bits per symbol delayed by half a ...
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43 views
Gnuradio fifo cntrl timed out looking for acks
I am using USRP N210 SBX for my experiment. It is a simple TX RX system with a tuning center frequency. I have uploaded the flowgraph.
I am connecting to the USRP using a remote server
CPU MHZ : 2300....
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1answer
39 views
LoRa sensing using USRP GNURADIO
I made a simple RF sensing using USRP N210. I am trying to detect LoRa transmission.
A LoRa Node is operating at 915 MHz with Spreading Factor 8 and bandwidth 500 kHz.
I have used a USRP UHD Source ...
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48 views
is it possible to introduce fractional delay in waveform in GNURadio?
I know this is a strange question as its hard to do in digital domain. I know it is a straight forward task if the signal is defined within N number of samples where I can go to Fourier transform ...
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1answer
46 views
How to use values from the output of a block in GNURadio
I want to use the output values of the top_block as a way of directing my flowdiagram. So I want the flowdiagram to take one path if the output of my processing ...
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62 views
QPSK transmission simulation
I am trying to simulate a QPSK transmission using GNU Radio following mpsk_stage6.grc example in Gnuradio tutorials.
Currently I have no idea where is the problem and everytime I execute the flow ...
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44 views
Packet Encoder GNU QPSK Transmission
Hello everyone!.
This is a template to QPSK transmission but Packet Encoder block is no longer available in new GNURadio versions, what do I need to replace this block in order to do a QPSK ...
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23 views
gnuradio - cpp block, cpu usage
I was working with message passing blocks (like es_trigger_edge, es_sink and more).
When I connected (using msg_connect) other block in c++ that I wrote, I have noticed that simple processing of the ...
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1answer
27 views
gnuradio - flowgraph with cpp
I build a flowgraph in gnuradio, generated python code, change a little and run it using python.
My question is, does building the flowgraph in cpp will provide better results (time)? (in other words ...
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65 views
Get data after “Correlate Access Code Tag”
in my Gnuradio flowgraph i have a stream of bytes that are 0x00 or 0x01.
Using the "Correlate Access Code Tag" block, I am able to insert a tag just after that a specific Access Code has ...
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1answer
225 views
Is Bluetooth Low Energy jamming possible with an SDR like the HackRF on GNURadio?
It seems like BLE jamming is technically possible by just jamming the 3 advertising channels 37, 38 and 39 https://github.com/lws803/BLE-jammer and it has been proven to work on an STM32 + 3x NRF24l01 ...
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1answer
180 views
GnuRadio CC Decoder or How to use FEC Extended Decoder
I am currently trying to recover a satellite signal, encoded following CCSDS standards. This includes a convolutional code with rate 1/2 and constraint length 7.
I am receiving the signal through an ...
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45 views
Finding time of arrival of signal using GNU radio
I am sending a repeating BPSK modulated PN sequence signal from a USRP x310 transmitter. I am receiving the sequence with another USRP x310. Both are attached to an octoclock. Is there a way to get ...
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1answer
118 views
Demodulating a satellite BPSK signal
I am currently working on a BPSK demodulator and decoder for a satellite communication system using GnuRadio.
The system uses a BPSK modulation at roughly 2GHz with a symbol rate of 200 ksymb/s. I ...
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201 views
ModuleNotFoundError: No module named 'custom_OFDM' with custom Python OOT Block [closed]
I am using gnuradio to develop custom OFDM blocks using Python. I have used gr_modtool to create my blocks and import them into gnuradio. When I try to run my flow graph using one of my blocks I get ...
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147 views
ADALM-PLUTO SDR with gnuradio on Macbook
I am looking to interface PlutoSDR with gnuradio on a macbook. I have gnuradio-companion installed, however, plutosdr blocks (source and sink) don't show up in it. Also tried installing iio-...
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155 views
Minimal frame sync in GNURadio for packet TX/RX?
I'm trying to do a minimal packet TX/RX using GFSK.
Signal at RX seems to be OK, but I can't get frame sync to work. This is my flowgraph and the signal I'm seeing:
As you can see, signal/bits at TX ...
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39 views
How to improve signal quality in SDR-to-SDR TX/RX test?
I'm have a GNURadio flowgraph with 2 SDR devices directly connected with an SMA cable. It sort of works, but I'm wondering if I can improve signal quality.
On the TX side, clean signal is generated ...
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1answer
62 views
Processing Wifi Packets
Im trying to use GNUradio 3.8 with an sdr to pick up some wifi packets 2.4 and 5 GHz but im seeing a ton of dropped samples from my sdr. Im wondering if my dropped samples have to do with the sample ...
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1answer
51 views
Cosine of amplitude 1 but GNU Radio shows FFT has amplitude > 30,000
I am doing an FFT on a cosine wave which has an amplitude of 1. The FFT is amplitude is not 1 but over 30,000. What am I missing here?
It's from the GNU Radio FFT wiki page:
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22 views
Slip rate for sliding correlator channel sounder in GNU radio
I have a spread spectrum channel sounder running the following transmitter and receiver:
[![tx][1]][1]
[![enter image description here][2]][2]
Imm not sure how to modify the slip rate between the ...
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47 views
Extracting rms delay, delay spread, and CIR from power delay profile
I have a spread spectrum channel sounder running the following transmitter and receiver:
When running it over the air (~2km), I get the plot of the correlator output:
I can see that there are peaks ...
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90 views
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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1answer
346 views
Sample rates, Samples per Symbol, and Digital Pulse Shaping
Having some confusion about digital pulse shaping for complex baseband (passband) signals. The complex baseband linear modulation equation is
$$s(t)=\sum_{m=-\infty}^{\infty}\text{Re}\{a_m\}h(t-mT)+j\...
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27 views
Gnuradio scaling on Ubuntu issue
I have problem with scaling on gnuradio. When i use more than one WX widget - which shows parameters of signal - i can't see last widget. How can I deal with this problem - just to scale scopes, and ...
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630 views
16 QAM GNU Radio
I have been trying to implement a transmitter receiver flow graph which uses 16 QAM. I am using a USRP B200 as the transmitter and a RTL-SDR as the receiver.
I used uhd_packet_tx.grc and ...
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152 views
Gnu Radio Constellation Receiver
I am trying to use gnu radio to transmit data from one SDR to another using a 16QAM modulation scheme. This is the diagram on the receiver side.
Looking at the constellation sink, the constellation ...
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1answer
324 views
Chunks to Symbols in Gnuradio 3.8
I am trying to follow this tutorial to build a flow graph with GnuRadio 3.8. However, I am unsure what settings should I use for Chunks to Symbols and get some errors when I execute the flow graph:
<...
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404 views
GNU Radio | Packet Encoder/Decoder alternative
Are there any alternatives for packet encoder/decoder (deprecated) in gnuradio3.8.0.0 ?
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284 views
Record Signal after Threshold Reach in GNU Radio
I would like to use GNU radio to begin recording a predetermined number of complex samples to a file sink automatically as soon as a signal magnitude threshold is reached. For example, as the gnu ...
