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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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 ...
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18 views

time division duplexing (TDD) with USRP B2xx

I am going to implement a real-time TDD link (in the order of one-millisecond burst durations) using two laptops and two USRP B2xx (in either single antenna or dual-antenna ways). I searched a lot on ...
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41 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 ...
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22 views

Will USRP processing data be affected by time.sleep in PythonOOT?

I recently used usrpb210 + OFDM to transmit data again. OFDM uses gr-digital / examples / ofdm/ tx_ ofdm. grc,rx_ofdm.grc, I can receive data normally every time I transmit, and the number of packets ...
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28 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&...
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29 views

GNURadio GFSK demod missing data

we are trying to develop a flowgraph for cubesat operation. Our flowgraph for includes both downlink and uplink parts in one flowgraph. It uses SoapySDR as a driver of an SDR. Most of the used blocks ...
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71 views

GNU Radio Low Pass Filter doesn't work as expected with different transition widths

I'm new to GNU Radio and signal processing. I don't know if the following is a simple question, but I have been scratching my head about it. I created a simple flow graph with a random source (0-3) ...
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25 views

Gnuradio running into audio underrun when using audio source and sink at the same time

I wanted to calculate the BER curve for an FSK audio modem transmitting via the speakers and receiving through the mic of the computer. I am using Aaron Scher's FSK loopback flowgraph The thing is, ...
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16 views

GNU RadioTagged Stream: How to clip the stream as "packet length" tag long

I am currently trying to develop a GNU Radio block which takes a tagged stream as an input. The tags keeps the length of the packets. But the distance between the tags and the packet length are not ...
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33 views

Undersampling in GNU Radio

I'd like to implement a FHSS receiver in GNU Radio, using a USRP B210. The total bandwidth of the signal is about 30 MHz, with each message having a bandwidth of about 200kHz. When I attempt to ...
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19 views

GNU Radio Vector output Receiving Error

I am implementing a GNU Radio block that takes an input signal as a stream and returns a vector stream. The code section is given below. The block is written to understand the mechanism (Therefore, it ...
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58 views

GNU Radio Stream Input-Vector Output

I successfully designed the transmitter block. I am now implementing the GNU Radio receiver block and using a Python (since it is easier for me to design a prototype) block that takes a stream of the ...
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50 views

GNU Radio, Frequency Hopping Spread Spectrum for High Hopping Intervals

I am planning to implement a frequency hopping spread spectrum transmitter and receiver in GNU Radio. In my project, the bandwidth of the message signal is around 200 kHz and the maximum frequency ...
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27 views

transmit signal with hackrf one

I want to use hackrf one to transmit a continuous signal. my question is that "can hackrf transmit signal continuously or it has certain interrupt between its transmission?" my question is ...
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1answer
67 views

Help understanding quadrature sampling and effective bandwidth

Let me start off by saying I'm at least a little embarrassed that there's something simple that I'm fundamentally not understanding here. Not sure if the blame is on me, or the prof that taught me DSP ...
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12 views

UBX could not transmit signal

I am new to x310. I want to transmit a signal with its UBX daughter board and using gnu USRP sink block . but it seems no signal transmitted. Is this a software problem or hardware?
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18 views

How to build a model for $2 \times 2$ MIMO using GNU Radio?

I have been trying to set up a GNU Radio flowgraph where I can implement a $2 \times 2$ MIMO system. don't know how to make spatial diversity using the blocks, also I am not sure which block ...
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85 views

Send real and complex signal from python to GNU radio. ZMQ Python SUB -> GNU Radio

I've been reading about this. To do this, you should use the ZMQ blocks instead of the UDP blocks because of data loss. Now when using ZMQ I have problems with the received signal, if I create a np ...
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18 views

Send complex signal and receive the same complex signal, GNU radio

I’m working on a project where I want to send complex symbols like 4-QAM, 8-QAM or 16-QAM for example and demodulate those symbols, the idea is to use the signals as points (like in the constellation ...
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50 views

Writing a BPSK Demodulator

As part of a larger project, I've been attempting to implement a demodulator for RDS, a digital transmission standard in FM broadcasting, in software with C++. I've easily been able to get as far as ...
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44 views

Frame synchronization for single carrier burst applications in fading channels

I recently started to implement communication systems with software-defined radios in GNU Radio. In my system design, I am planning to transmit data in burst mode, the frames will be not sequentially ...
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36 views

How to recover modulation symbols?

I am using GNURadio to send and receive a limited number of modulation symbols. I have constructed the following flow chart:random source(no repeat)->chuncks to symbols(file sink1)->polyphase ...
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84 views

GNURadio Guided Tutorial PSK Demodulation Example

I have been reading and doing the steps on this webpage of GNUradio : https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation In the middle of the page, there is a section: "Using ...
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53 views

Spectrum Smoothing

I recently stumbled upon this GNU Radio flow graph which smooths spectrum. Block parameters are seen in image attached below. Also visually results doesn't change if I take out "Keep 1 in N" ...
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1answer
75 views

Reed-Solomon error correction in GNU Radio

Can someone please explain how to define parameters for Reed-Solomon decoder correctly in GNU Radio? I have already looked at ETSI EN 300 744 Clause 4.3.2 , but it does not explain how to choose ...
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79 views

How to decode a binary Signal in a wav file into binary - sent here from stackoverflow

I'm doing a puzzle that gets me to call a phone number which produces a load of beeping sounds. Putting this into audacity as a spectrogram produces this: Zoomed in it looks like this: This looks ...
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Why the output data quantity of the channel model in gnuradio is less than its input data quantity?

I am facing a problem and I have created the following flow diagram to illustrate the problem. As shown in the figure, my input is 0,1+1i,2+2i,...,199+199i, I set the parameters of "channel ...
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72 views

Digital Selective Calling (DSC) Decoder in GNU Radio

I’m attempting to develop a GNU Radio FSK decoder for Digital Selective Calling on marine VHF but I seem to be stuck. I got my hands on a Standard Horizon handheld marine VHF unit with DSC capability ...
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67 views

How can I fix bad clock recovery for bursts with short distance?

I use GNURadio as a prototyping tool to build a receiver for a digital signal of a home appliance. The signal itself looks good so far. Also the symbol synchronization works well using the symbol ...
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57 views

Decimation with dynamic factor in GNU Radio

In a GRC flowgraph I have a custom OOT block which periodically sends a PMT message to the "command message port" of the "UHD: USRP Source Block" (for set the RF center frequency ...
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65 views

Implementing OQPSK in Gnu Radio Companion

I am currently trying to realize this block diagram in Gnu Radio Companion: Before using a file source block with the binary I want to send, I plan on just using a vector with an alternating 1,0 ...
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225 views

Relationship between sampling rate and bandwidth in gnu radio

I wondering something. While working with adalm pluto sdr in gnu radio, the sample rate I enter in the source block is actually bandwidth. I know that bandwidth must be half of the sampling rate ...
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27 views

To GNU Radio users - how you find a block class writing own python code using GNU Radio library?

How are you guys finding an interesting block class among available GNU Radio modules? I find it difficult to write own flowgraphs writing in python. Assume I want to use Constant Source block, I ...
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45 views

Chunks to symbols block, what is the use of 'dimension' parameter?

Can somebody explain me what is the use of 'dimension' parameter in Chunks to Symbols block in GNU Radio? As far as I understand it relates to dimensions in symbol table given as a first argument, am ...
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30 views

wireless card in place of an antenna/ hack a robot

My nephew has this toy robot and asked me to build a new remote for it. It's a "Cady Wida" robot from JJRC. When I opened it up, a tag inside said "40 MHz" and the board sported a &...
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94 views

AWGN noise variance in upsampled BPSK signal

When I simulate BER for basic PSK schemes, I set the IQ complex noise variance to $\sigma^{2} = \frac{E_{s}}{2*R_{m}*R_{c}}*\left( \frac{Eb}{No}\right)^{-1}$ where $E_{s}$ = Energy per modulated ...
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67 views

GNU Radio filter normalization

I have noticed that all filter taps from the firdes class are normalized by dividing them over the sum of all taps magnitude, as shown in the example below for Gaussian Filter. Is this normalization ...
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64 views

oQPSK/QPSK conversion with fractional interpolation

I once used a GNU Radio QPSK receiver for oQPSK demodulation. All I did was to "forcefully" delay the Q channel by half the symbol time. At the time, I was using a discrete number of samples ...
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2answers
51 views

GNURadio signal degradation *above* Nyquist rate

I am going through the basic tutorials for GNURadio, and I have a question related to the sample rate tutorial. In it they demonstrate the degradation effects of sampling at too low a sampling rate. I ...
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33 views

Comparing self-made O-QPSK signal with Zigbee burst (Q-QPSK acc. to IEEE 802.15.4)

What might be the cause of the worse baseband demodulation result of the bottom VSA screenshot compared to the demodulation result shown in the top screenshot ? Randomized Q-QPSK signal generated by ...
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270 views

Clock Recovery with FSK Demodulation in GNU radio

I'm working on demodulating an fsk signal sent from a cubesat on the ground to an antenna station. I'm trying to do it in GNU radio but I am not quite getting the original signal back. The cubesat ...
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37 views

Gnu radio C++ on Ubuntu 16.04

I've read posts that Ubuntu 16.04 is not a good fit for newer gnuradio. Since I can't update Ubuntu so I had to install 3.7.9. It works fine except the C++ part. Because GRC won't generate C++ code (...
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82 views

GNURADIO Busports and channel map for polyphase channelizer block

I am trying to implement the channelizer presented in this paper given in this link; http://www.trondeau.com/examples/2014/1/23/pfb-channelizers-and-synthesizers.html. However, I am experiencing a ...
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1answer
84 views

Gnu Radio symbol recovery

I have successfully built Simulation example: FSK. Everything works fine and I'm getting same results as in example. For the next step I would like to save demodulated binary data in file but I'm ...
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134 views

2FSK implementation with VCO GNURadio

I am fairly new to GNURadio. I am trying to generate a 2FSK with minimum frequency shift. Instead of multiplying with a 8MHz complex carrier, I directly use VCO to generate two frequencies. One at 7....
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66 views

GNU Radio head block doesn't finish simulation

My task is to generate finite number of samples and save it to the file. For that purpose I used head block but after setting the run option to: Run to Completion, the flowgraph doesn't stop, just ...
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107 views

GnuRadio additive scrambling/descrambling

How are you supposed to use GNU Radio additive scrambler block? The wiki documentation is very vague on the subject: Scramble an input stream using a Linear Feedback Shift Register (LFSR). This block ...
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109 views

pi/4 QPSK modulation/demodulation in GNU Radio

Is there any quick mechanism to create pi/4 QPSK or pi/2 BPSK modulation scheme in GNU Radio using Constellation Modulator object or Constellation Object? Or I need to write it by myself? Thanks in ...
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246 views

Clock recovery using Mueller and Muller adds noise affecting EVM or SNR (Two cases - GNU Radio & Python code)

The implementation of the Mueller and Muller clock recovery that I am seeing adds a large amount of 'noise' or degradation to the Error Vector Magnitude (EVM) to the symbols on the constellation. This ...
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87 views

SDR and amplitude modulated signals

Can I view every signal that has been transmitted using software defined radio as a amplitude modulated signal? For example I could make a frequency modulated baseband signal in GNU Radio and connect ...