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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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 ...