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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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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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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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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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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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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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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69 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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49 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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52 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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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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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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22 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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49 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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46 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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30 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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57 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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151 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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214 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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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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130 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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157 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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124 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 ...
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76 views

GNU radio, FSK channel estimator

A quick question, is there any way to do channel estimation on a (G)FSK receiver. I'm trying to build a DASH7 receiver. I found that there is a block for a OFDM channel estimator, but i can't find ...
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363 views

Symbol Synchronization for GFSK/FSK signals in GNU Radio

I am trying to demodulate GFSK signal, and extract the packets using GNURadio. TX information: It is basically BLE transmission but customized. BW: 2MHz, data rate: 1MSymbols/sec, 1 bit per symbol. ...
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Increasing samples per symbol degrades correlation between signals

I am trying to implement a simple pseudo-noise (PN) ranging simulation. I have used this GNU Radio example, and I have adapted it a bit to suit my needs. Here is a screenshot of my flowchart: The ...
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49 views

How to correct for delays in a PAM-X signal with orthogonal CDMA?

I have a receiver which receives data bits at a rate of 5kbit/s. The number of data bits per burst is low (say, 16 bits). These databits are obtained after despreading the incoming signal using an ...
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94 views

Phase difference calculation for non divisible sample rate to frequency

I am learning DSP and I am trying to simulate a simple phase difference calculator between two sinusoidal signals using GNU radio. My flowchart looks like this: As can be seen on the chart, one of ...
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39 views

Strange signals in wifi channel

I am currently working with a USRP B200 mini-i to receive 802.11 signals from various usb wifi devices. When sending packets with the USB device over a channel, lets say 2.412GHz, i can't really see ...
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112 views

Proper way to detect and decode transmission in gnuradio

I am receiving AM modulated data over USRP. I successfully receive the data using an IF frequency (i.e., offset from the carrier), apply a highpass to remove RXLO phase noise and then downmodulate the ...
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OQPSK - GNU Radio Companion

I was wondering if anyone has had any success in implementing OQPSK in gnuradio. I have a working theory of expanding on the Constellation Modulator to include a custom OQPSK function. I have ...
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100 views

gnuradio extremely sluggish with QT (but seems OK with WX)

I am evaluating gnuradio with Ettus USRP X310 and 2xUBX-160 daugterboards, connected via GBit ethernet to a new Lenovo laptop running Win10 and gnuradio 3.7.13.5. I am testing it with the most basic ...
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678 views

I wish to create a GNU Radio program in C++ that doesn't need GRC or Python, is there a reference or template for this?

I want to create a functionally equivalent C++ file to the Python top_block.py file that is generated by GRC when executing a (blank example) flow chart. I know that C++ can be used to define blocks ...
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GNU Radio - Bandwidth and Band Reject Filter

I am currently trying to generate a psk modulated carrier with gnu radio. Attach is an image of my flow graph. As can be seen I am generating a bit stream using the Random Source module and ...
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109 views

RSP1A sample rate vs if bandwidth

I'm using the RSP1A SDR and I want to understand how to choose the best configuration for receiving a signal of 125 khz bandwidth. I would like to know if when choosing the option 200 KHz IF ...
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GNU Radio - General Filtering Questions - Any feedback is appreciated!

This is a fairly general question I feel like. So, the scenario I am presenting is this: I am generating random data using the random source module and feeding that data into the Constellation ...
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111 views

How to setup filters to catch 4FSK deviations

I'm trying to demodulate a radio signal from Motorol DP4801 (MOTOTRBO) that follows DMR specification. I'm receiving the signal by using HackRF with the rate sample 1 MHz. The radio uses frequency ...
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GNU Radio | Grouping just 24 consecutive soft bits from a repeating tagged stream onto 3 bytes, starting from a specified tag

A vector source [0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,1,1,1,1,1] produces repeatedly a tagged stream with one tag, ...
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494 views

How to adjust receiver gains to avoid saturation and quantization noise to optimise post digital processing?

I am using a Hack RF One as SDR and the software GNU Radio to receive and process signals emitted from a drone. Given that the drone is moving and is emitting signals from a wide zone, received signal ...
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131 views

Having trouble transmitting/receiving a BPSK signal using two USRPs

I am relatively new to working with SDRs and GNURadio and I am attempting to generate a BPSK signal and transmit it through one USRP and receive and demodulate it on another USRP. I am using GNURadio ...
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252 views

GNU Radio GMSK modulator

I'm looking at the GNU Radio GMSK modulator block. The Gaussian taps are somehow convolved with a rectangular window with 4 * samples-per-symbol taps owing to the fact for GMSK, the filter spans four ...
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563 views

Not sure why I get errors of missing blocks when trying examples in Gnuradio Companion

I just started working with GNURadio without much of familiarity about this software. I found a couple examples online and I tried to run them but I get many Missing Block errors. Thats how it looks ...
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Synchronization and downsampling after matched filtering - GNURadio polyphase clock sync

I am trying to model a QPSK transmission. For this, I am using the software GnuRadio and more specifically the block polyphase clock sync. This block performs timing synchronization for PAM signals by ...
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152 views

Impact of the sample rate of the emitting signal : communication between HackRF One and USRP NI 2921

I am transmitting a 1 kHz cosine wave with a HackRF One. I receive it with a NI2921 USRP at a sample rate of 200kHz. All the process is on GNURadio Companion. I changed the sample rate at emission ...
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38 views

SDR : Signal divided between the edges of the receiving window

I'm using a SDR (specifically the RTL-SDR) to analyse the spectrum and i noticed a phenomena that does not seem logical. The signal I want to capture is centred on 868.3 MHz and the central ...
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162 views

Communication between two USRP : mismatched spectra between transmission and reception

I am trying to make two USRP communicate between each other : for the transmission, I'm using an HackRF One USRP and for the reception a NI 2921 USRP. As a first test, I'm trying to send different ...
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230 views

How can an SDR recover a high-frequency signal?

How can software-defined radios operate at high frequency? The Nyquist rate dictates that you need to sample at twice the frequency to fully recover the signal. If my signal of interest is modulated ...
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270 views

QPSK Phase Recovery : Maximum-likelihood Vs Costa's Loop

I have implemented a QPSK Costa's loop in GNU Radio and run some BER benchmarking. All is going well. Out of curiosity, I'm trying to implement the Maximum Likelihood phase recovery shown below. For ...