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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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How can I ensure that I am transmitting at a certain baud rate using GNURadio, PlutoSDR, and GMSK modulation? What is the relation to samples/symbol?

I am new to signal processing, so this post may not be properly phrased, but I am attempting to use GNUradio to send a GMSK-modulated string to a CubeSat that my club is ground testing. The satellite ...
jtn050's user avatar
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GNU radio create custom source

I want to implement the signal $$x(t)=4\cos2t+5\sin30t+5$$ $$0<=t<1$$ GNU Radio has source blocks: but the waveform is continuous over time,I want it to start at $t=0$ and end at $t=1$. What ...
ElectronicsBeginner's user avatar
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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. ...
Aleksander's user avatar
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FM0 (bi-phase space) decoder

I'm looking for the solution for decoding FM0 (bi-phase space) encoded signal from RFID tag. Response from the tag starts with preamble and then followed by 16 bit random number. Link rate is 40kHz. ...
rf-engineer's user avatar
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GNU Radio can't find my USRPB205

I connected my USRPB205mini-i and tried running the following flowchart but I keep getting, RuntimeError: LookupError: KeyError: No devices found for ----- Empty Device Address Here's the rest <...
Bryan Busby's user avatar
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How to extract data from .iq file?

I am trying to extract data from .iq file recorded by radio. The modulation is QPSK. I have implemented a GRC flow graph but the costas loop is not converging. Can anyone please help in understanding ...
comspec's user avatar
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Why don't two multiplication of the same cosine wave let me come back to the original baseband signal but instead shifts it further?

I'm trying to do a simple modulation and demodulation of a digital/binary source. I'm multiplying it by a 1khz cosine to center it at 1khz instead of 0. Then, to demodulate, I multiply again with the ...
allexj's user avatar
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Does Filtering changes the noise characteristics in a signal?

So, I tried out what i am learning in digital communication using GNU radio. The plan is to modulate two baseband signals(sine and cosine) 1kHz with no modulation protocol(don't know any(yet)) to a ...
qwerty's user avatar
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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: ...
Gabriel's user avatar
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USRP X310 not receiving anything but noise

I have been trying to receive different types of signals using a USRP X310 but all I can receive is noise. I tried different types of antennas and designed many different kinds of blocks but I get ...
Ahsan Yousaf's user avatar
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I'm struggling to understand the FIR Filter and its application

I'm new to GNU Radio, and I was watching this video However, I didn't quite understand the purpose of the FIR Filter. I know what decimation or downsampling is because I have the book "Digital ...
ed190's user avatar
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Recording a wav file using GNU Radio instead of other software

I originally made this flow diagram to process signal in real time from cubesats that have a cent-freq of 437 MHz, but I want to record signals to anaylize later the wav file so . However, I want to ...
ed190's user avatar
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Stream gate - removing samples from timeline. Pitfalls?

I'm working with gnuradio. What I want achieve is extract signal from full stream by some kind of stream gate (based on tags) and after that write to file only timeline where signal exists. In my case ...
brz's user avatar
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2 votes
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Can you please help me in generating a chirp signal in GNU radio by creating a module of your own?

I am currently working on a FMCW radar using a SDR I have done the simulations in python and am moving towards simulations on GNU radio. In python it was easy to generate a chirp, just use the scipy....
Raj Patil's user avatar
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Can't get GNUradio PLL Frequency Detector to work

I am trying to implement doppler logging of the carrier frequency of a phase modulated satellite downlink signal. I tried implementing this using the "PLL Frequency Detector" block in ...
Nils's user avatar
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Add delay to messages in GNURadio

I want to add a delay to the messages in GNURadio. For example, when I click on a button, some action will not be triggered immediately but after specific delay. I think this behavior can be ...
ALEX's user avatar
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Using GNU Radio to perform EVM measurements

Is there any previous work describing the implementation of an Error Vector Magnitude (EVM) measurement system using GNU Radio? The system in question is made of an SDR HW platform, e.g. USRP, ...
Antonio Fernandez's user avatar
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TX RX text via gnuradio using hack rf

I have a problem here - either I'm stupid or my hack rf is broken I am trying to send text via 2 hackrf like in this tutorialusing GMSK The simulation returns the text is correct, but when I run the ...
Nortan's user avatar
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What is the correct way to send bursts of data in GNU Radio?

I have a GNU Radio flowgraph where I send bytes (preamble, header, payload) from an external python program to the flowgraph through a ZMQ socket. The bytes are then modulated in the flowgraph and ...
Aleksi R.'s user avatar
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How to correctly accept Polar/LDPC encoded bits with PSK modulation?

I have implemented a packet reception and transmission scheme using QPSK. Next I decided to add Polar/LDPC encoding. As a result, nothing is written to the received file. I think the thing is that I'm ...
Ice Cool's user avatar
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OFDM does not work with USRP

I found the ofdm flowchart in the Gnu radio examples.(ofdm_loopback) Scheme: The spectrum and the received data of the received signal: After that, I connect the USRP Sink and the USRP Source. The ...
Ice Cool's user avatar
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Is there any way to fix USRP that doesn't connect?

I am new to SDR. But I have an USRP X310. Installed UHD and GNU Radio from source on Ubuntu 20.04. Connected to the USRP with SFP+ through the port 1 and powered the USRP. But the LED of the ethernet ...
Azamat Nassipkaliyev's user avatar
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Demodulating 7x Sequential BFSK Signals

I'm hoping someone could help me find a demodulation approach to an FSK signal contained in wav files that has 14 unique, and evenly spaced channels. They appear to be separated into 7 BFSK pairs. I.E....
T.C.'s user avatar
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Phase Measurements of OFDM Signal with USRP

I am doing some analysis on a received OFDM signal using USRP N210 with GNURadio. Figure OFDM RX shows the OFDM receiver (please refer to GNURdaio workshop slides) . The transmitted OFDM signal is ...
wesam amiri's user avatar
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numerical time differentiation in GNURadio

I'm hoping to put together a cheap modulation monitor for wideband FM radio using an rtl sdr usb, on the FCC website, it's listed that the modulation percentage for an FM station is the actual ...
Jacob's user avatar
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USRP Frequency Drift Measurement

I trying to measure the frequency drift between two N210 USRPs using GNURadio Companion. I used one USRP as a TX and the other one as an RX. The transmitted signal is a complex sinusoidal. The issue ...
wesam amiri's user avatar
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512 views

How to implement a Basic Embedded Python block in GNU Radio flowgraph?

I am trying to create a GNU Radio flowgraph for identifying a predefined preamble in satellite telemetry packets. For instance, the preamble can be "SAT_SAYS_HI". After identifying this ...
AP666's user avatar
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A vanilla BPSK set up, but constellation disgram is a line

I set up a vanilla BPSK modulation in GNU-radio, but the constellation is showing me a line. I am using: ...
Xingda Chen's user avatar
1 vote
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151 views

Is using Quadrature Demod for MFSK demodulation a good idea?

I'm experimenting with MFSK in gnuradio, and seem to be quite successful simply using: quadrature demod on the raw data to get the frequencies RRC filter clock sync on that Constellation decoder with ...
Thomas's user avatar
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Why does one of my OFDM subcarriers have a much higher gain than the rest in GNUradio?

I'm using a fairly standard setup after the ofdm flowgraph examples provided by gnuradio. When I look at the absolute value of the received complex symbols in the first sync word (and every other ...
eee's user avatar
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2 votes
1 answer
269 views

USRP N310 RX gain lower than other SDR with same GNURadio script

In my company, we are using a GNURadio script with a PlutoSDR to receive packets coming from a transmitter located very far away. The receive power is really weak, our antenna is receiving something ...
Amaury's user avatar
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1 answer
59 views

gnuradio , SDR usrpx300

I use usrp x300 SDR. I'm confused about Bandwidth and sample_rate. How do I calculate them? is ...
Rami Mrzk's user avatar
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1 answer
629 views

What is the frequency coming out of VCO in GNU Radio?

Based on the numbers, can anyone tell me what Sensitivity means in VCO block. This is what I found so far, but do not understand it. Sensitivity units are radians/sec/(input unit)
Jack's user avatar
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FM Receiver and Delay simulation GNU Radio - Issue with modifying Delay block in run-time

I'm actually doing a FM receiver with an antenna linked to an USRP N210 and demodulate it. I have two channel: one with delay and one without. I set my delay in seconds (...
Tamala's user avatar
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1 answer
461 views

Interpolate & sample period GNU Radio

I've a little question regarding interpolation in GNU Radio: I'd like to do an interpolation (by a factor of 2) and be able to change the sampling period of the samples interpolated but im having a ...
Tira's user avatar
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Research on SDR security Gnu Radio and legal transmission with filters

In fact, I am doing research around SDR and possible dangers. Then I stumbled upon the most well known "replay attack". Via Black hills, I came across the following diagram in gnuradio: The ...
HereToLearn's user avatar
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1 answer
373 views

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 ...
Thomas's user avatar
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259 views

GNURadio 3.8 QPSK : Hard time to recover the right symbols/data

Cheers, I am demodulating a QPSK signal on GNURadio, the data transmitted is a known HEX file with the "1ACFFC1D" foreword every 124 bytes, to check if the demodulation is a success, it ...
Ed_Sheherazade's user avatar
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1 answer
56 views

Why aren't I getting my expected FM channel when multiplying these two frequencies?

Hope y'all are doing well. Recently I've picked up a LimeSDR and interfacing it with GNURadio and been having a blast with it. I got my first FM receiever demo working using examples from LimeSDR FM ...
Pllsz's user avatar
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1 vote
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54 views

Envelope of a series of pulsed signals [duplicate]

I need to record a series of pulse waves for an experiment. The recording is done via Software Defined Radio (GNU Radio). The pulse waves are modulated in such a way that the amplitudes of each single ...
thehnm's user avatar
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124 views

gnuradio: eCPRI link implementation for LTE

Need to build eCPRI link in xRAN network between eRE and eREC devices. In eRE I'm capturing via osmocom source (SDR device) and I have a stream of float32 complex IQ numbers as usual output. Now I am ...
Sabyrzhan Tasbolatov's user avatar
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1 answer
199 views

How to measure NB-IoT signal quality with GNU Radio?

I need to measure the quality of an NB-IoT signal. Is it possible to obtain RSRP, RSSI RSRQ or SINR using GNU Radio?
Nicolas's user avatar
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What are these mysterious spike after the FIR filter?

The main paramter of this fir filter in flowgraph: Decimation:1 Cutoff freq:8KHz Transition width: 1KHz I have a very simple FIR test in Gnuradio ,the flowgraph is below: When I change the signal ...
Thomas Anderson's user avatar
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119 views

Problem to extract value from complex_to_mag_squared GNURadio block

I am trying to dissecate a large bandwidth into smaller ones and, for each of those smaller bands, see if it contains enough energy to consider that a message is sent in it. To do so, I am thinking of ...
aheuchamps's user avatar
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421 views

How to downconvert NB-IoT signal using GNU Radio

I have captured an NB-IoT signal to a file (I-Q samples) using GNU Radio. The signal is centered at 768.2 MHZ and has a bandwidth of 200KHz. I need to downconvert the frequency to 767.8 MHz also using ...
Nicolas's user avatar
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58 views

What cause amplitude changed after `multiply`?

In Gnuradio,multiply 2 signals as below,max amplitude should be 1*2=2. Output shows the max amplitude beyond 2,around 2.4. What's the reason?
kittygirl's user avatar
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116 views

How do I set GNU Radio Es/No?

I am trying to create a random signal in GNU Radio (using DVB-S2 specs for the physical layer) and transmit this signal using a USRP X310. This is shown below: Problem: I would like to be able to ...
Matthew Hilts's user avatar
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423 views

EVM reduction for GNU Radio GMSK quadrature demod using Wiener equalizer

I have been exploring different ways of improving the EVM performance of quadrature demod block for GMSK demodulation. As we all know, the Gaussian filter introduces intentional ISI, which can be ...
Moses Browne Mwakyanjala's user avatar
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815 views

How do I Correlation Estimate both for a pattern and its inverse in GNU Radio?

I'm using the Correlation Estimator block in GNU Radio before my Symbol Sync block, in order to more quickly and reliably clock the signal. My problem is that the data is sent as NRZ with ...
Thomas's user avatar
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182 views

GNU Radio and USRP audio source problem

I have a modem which accepts a voice in GNU Radio, digitizes and compresses it (codec2) and transmits it using USRP on one laptop and receives it on another laptop. When I use "Wave File Source&...
Ali's user avatar
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