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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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Creating GNU radio flowgraph for continuous switching between transfer and receive mode

I am having a hackrf-one device which can either transmit or receive signals. I am having a GNU radio flowchart which has a selector block which allows manual switching. I am not able to switch it at ...
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1answer
63 views

Can a software defined radio with a frequency range of 300 MHz – 3.8 GHz detect AM (535 to 1705 KHz) and FM signals (88 to 108 MHz)?

I am interested in knowing whether BladeRF SDR with a frequency range of (300 MHz - 3.8 GHz) detect AM and FM frequencies? Also, how important is the sampling rate of the SDR. For example, BladeRF has ...
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1answer
62 views

Residual carrier tracking with PLL

Residual carrier systems such as PCM/PM/NRZ and PCM/PM/Bi-phase are common in space applications. Compared to suppressed-carrier systems such as BPSK, the literature sources on residual-carrier ...
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97 views

EbNo, SNR, and BER simulation for BPSK with convolutional code

Im currently simulating BER performance of CCSDS convolutional code. Im having some troubles in specifying EbNo and SNR in gnuradio blocks. From matlab webpages on BER simulation for RRC pulse and ...
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41 views

How can I tune into two FM frequencies at the same time?

I have a file source for a FM radio capture and have a working FM tuner. I need to tune into two frequencies and listen at the same time. Any help to accomplish this would be appreciated! Current ...
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52 views

Phase noise modeling using gnuradio IIR filter

I need some advice regarding phase noise modeling using gnuradio IIR filter. I'm trying to synthesize phase noise (multiplicative) with a given noise mask. In one paper, the authors were able to ...
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27 views

Group delay emulation in GNU Radio

I'm trying to test an equalizer against group delay distortion of a satellite communication link. According to the CCSDS standards, It is agreed to simulate high-order modulation system with in-band ...
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1answer
92 views

GNU Radio loop bandwidth normalization

From GNU Radio documentation, the control_loop block proposes loop bandwidth values in the range $[\frac{2\pi}{200}, \frac{2\pi}{100}]$ in radians per sample. Some blocks, like the new timing symbol ...
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29 views

“Image Processing” [closed]

I'm an Italian student. I'm studying Gnu Radio and I would like to upload a photo, can I upload it with "file image source" or other blocks? I need to make FFT of an a image. -> image 2D Thank you ...
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1answer
65 views

Recovering data from mystery signal

I was scanning the airwaves using my RTL-SDR and found a signal being broadcast locally that I was able to receive. When I configure the SDR Console V3 software to NFM, I get the following audio. (Wav ...
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1answer
173 views

Why am I seeing a negative frequency on FFT graph in Gnu Radio Companion? [closed]

I have a pretty simple flow here in GRC, but for some reason I'm seeing a negative frequency mirroring the 10khz signal that I'm generating. What's causing this negative frequency to show up in the ...
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1answer
101 views

am I recording LTE uplink signals?

I have this app in my phone which tells me the LTE UL frequency and power: so I went with my SDR and measured the received signal at that frequency: Now, how can I be sure this is the transmitted ...
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0answers
82 views

Dynamic loop bandwidth for a Costas loop

I'm using a Costas loop for carrier recovery. The BER vs SNR (from GNU Radio Simulation) curve for different loop bandwidths (0.03,0.05 and 0.07) is shown in the graph below. It can be seen that the ...
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1answer
72 views

Emulating a Variable Delay

I am trying to emulate a satellite link where the delay time between the satellite and ground station changes over time due to the satellite's motion. I plan do this by converting to the frequency ...
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0answers
35 views

Band-edge filtering for an RRC pulse-shaped manchester/biphase-encoded bitstream

Band-edge (derivative matched) filters can be used to generate an error signal for frequency locked loops (real part) or symbol timing loops (imaginary part). The derivation of the band-edge filters ...
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99 views

Blind equalization with constant modulus algorithm in GNU Radio

I'm currently simulating the effect of multitap channel on BPSK as well as its remedy i.e. equalization. The modem is expected to work with satellite TT&C transponder. The communication channel ...
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1answer
458 views

Pulse shaping with RRC : Number of taps

I am running a BPSK flowgraph in GNU Radio which is based on RRC pulse shape. I noticed that the BER is quite poor when the number of taps is low. However, using the number of taps around $20\times ...
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1answer
40 views

Analog equivalent for transition width in Digital radios

I have started off with GNUradio and I am not sure if I understand the transition width parameter available in GNU radio companion filter blocks . As per online documentation transition width of a ...
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1answer
182 views

Timing recovery in GNU Radio : Variable rate vs Fixed rate operation

I have been wondering about the implementation of timing recovery blocks in gnuradio. In literature, for asynchronous sampling, all that is needed are error detector (MM, ML, Gardner etc), a loop ...
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165 views

GMSK/GFSK BER simulation in GNU Radio : How to specify signal energy

In GNU Radio, BER vs SNR can be measured by fixing the signal energy and varying the amplitude of the noise source block. For example, in BPSK, we have transmitted signal $s\left(t\right)$ with a ...
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739 views

GNU Radio polyphase clock sync block: how do I use it?

I'm trying to receive some simple PSK real world signal with a sdr and GNU Radio The problem I currently face is « how do I use the polyphase clock sync block ». I read https://wiki.gnuradio.org/...
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258 views

Carrier recovery with the Costas loop : PLL pull-in range

I have created a channel model in GNU Radio (a modified version of the default GNU Radio Channel Block). Its performance under AWGN (without timing, phase or frequency offsets) aligns properly with ...
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1answer
311 views

PLL phase and frequency characteristics

I'm currently working with BPSK carrier phase and frequency recovery in GNU Radio. I have been able to use Costas loop and Frequency locked loop (four carrier acquisition) which are based on the ...
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30 views

find power of recieved signal of usrp b200 in gnu radio companion

how to find power of recieved signal of usrp b200 in gnu radio companion from frequency sink block (the frequency plot) or any other block available in gnu radio. I am transmitting and receiving ofdm ...
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271 views

Why does my OFDM demod in GNU Radio not return anything?

This is the flowgraph I used: Output after mod: Output after demod: I've read that it might be a synchronization problem but since I'm not actually transmitting anything over a medium, that shouldn'...
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1answer
163 views

BER vs SNR simulation for GFSK modulation (Closed-form BER for GFSK)

I'm in the process of simulating the performance of a GFSK modem in GNU Radio. I have managed to get a curve similar to the curves I see in a number of literature sources. However, I need an accurate ...
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2answers
479 views

GNU Radio QPSK 4 Symbols

I'd like to generate a simple QPSK signal in GNU radio, but so far I haven't been able to get it to perform the way I'd like and I'm not sure if this has to do with some misunderstanding I have about ...
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64 views

Satellite receiver suite

I'm in the process of implementing a general purpose baseband system for modulation schemes (Linear + CPM) commonly used satellite and deep-space TT&C as shown in the functional flow block diagram ...
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0answers
249 views

Software Defined Radio samples analysis using gnuradio and python

I'm trying to replicate what gnuradio is doing in "pure" python with a hackrf. Having mixed result, I decided to use the same data to compare the outputs I obtain. My gnuradio workflow is the ...
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1answer
148 views

AM demodulation from a real RF signal

I'm capturing an RF signal transmitted at 433.8MHz, with a bandwidth of about 50KHz. My goal is to be able to save it as a .wav file. I'm using an RTL-SDR dongle and a software named HDSDR, where I ...
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0answers
66 views

USRP Gain Problem [GNURadio / Matlab]

I'm having a problem figuring out the noise floor of my USRP. Receiving on the USRP with no antenna attached with Matlabs USRP integration I get noise around 0-80 (magnitude of real portion) when I ...
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811 views

USRP + GNU Radio as 1 GHz bandwidth spectrum analyzer

I have maybe not trivial but some interesting question. I need to create 802.11ac channels spectrum analyzer with USRP. Hardware: USRP B210 Software: GNU Radio 3.7.9 PC: Intel Core i3 i3210m 16 GB ...
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467 views

Help with OQPSK Demodulation with GNU Radio

I am working on demodulating/decoding the GOES-15 satellite EMWIN signal @1692.7MHz, BW: 50KHz Mod: OQPSK. I have minimal experience in signal processing and some experience in using GNU Radio. I have ...
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2answers
2k views

How does transition width of a low-pass filter affect a message which is well within the pass-band?

I'm taking a communication systems course and we use GNURadio in the lab. In an exam, we had a simple question where we were asked to demodulate a Dual Side Band (with carrier) AM signal in GNURadio. ...
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0answers
565 views

gnuradio: How can I change the value of the tag exiting the “Correlate Access Code - Tag” block?

Background: I have built a conventional demodulator in gnuradio and am trying to send payload data out of the flowgraph to an external Python script. I'm using gnuradio v3.7.12. It seems to me that ...
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297 views

GNURadio Sending Short Packets

I'm trying to create a basic GNURadio flow graph that will transmit a short message in order to receive an appropriate reply back. I currently have the following flowgraph: I have a program that ...
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1answer
2k views

How do I extract data from a gnuradio flowgraph now that the message sinks have been deprecated?

Background: I am writing a Python script that contains a gnuradio flowgraph object used to demodulate incoming IQ data. The flowgraph is started and runs while I periodically poll it for demodulated ...
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1answer
99 views

Better way to mute fundamental baseband frequency?

I'm working on a project to monitor the fluctuations and harmonics present on standard 120VAC mains power. I built an adapter that drops the voltage from 120VAC to 12V and then down to 0.5-0.6 VAC ...
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1answer
452 views

What kind of modulation is this?

I'm trying to find out what kind of modulation and encoding is used by my window cover remote control, aiming to implement the same on a Raspberry Pi to add a bit of home automation. A colleague ...
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1answer
676 views

Avoiding DC spike while decoding FSK signal

I am using the Quadrature Demod module in GNU Radio to decode an FSK signal, but the signal is appearing quite noisy. It has two distinct peaks centered around the advertised frequency, but they are ...
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2answers
467 views

Use GNU Radio to extract information from a VOR signal

I want to design a GNU Radio project to extract the information of a VOR signal, then find the angle to the north and the Morse code of the station. Is there any example that shows how to do it?
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189 views

how can i use gr-specest in gnuradio? [closed]

hello Pr how can i use the fam and the gr-specest in the GRC for cyclostationary features ------------------------------------------------------------------------
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0answers
155 views

Unable to stabilize 8-PSK signal with self designed costas loop

I am trying to make a signal processing block which implements the costas loop to stabilize an 8-PSK signal. Here is the flowgraph with "costas_loop" being my block. My workflow is the following - <...
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0answers
340 views

How can I perform timing recovery from the envelope of PSK signals?

I'm trying to reimplement FDMDV in GNU Radio, largely for educational purposes. It consists of 15 PSK subcarriers, 75 Hz apart, 50 symbols/sec each. The center one is BPSK and alternates phase each ...
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1answer
96 views

Frequency components much less prominent at the receiver for multiple tones

I am trying to transmit a multi-tone signal from one USRP (N210) to another and have written an out of tree block to generate the multi tone signals using an ifft. The two USRPs are connected directly ...
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247 views

Time recovery - GNU Radio

I read about Time recovery (as an example, the Mueller&Muller algorithm); it is linked to when you should sample your signal. I am currently working on a project with GNU Radio and there is ...
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1answer
717 views

O-QPSK constellation interpretation - GNU Radio

I am currently trying to recover the I&Q of a O-QPSK signal generate from the standard XBEE arduino module using a B200. I can get somehow get a "look-like" of a constellation. Here an screenshoot:...
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1answer
1k views

Possible to Derive Receive Signal Power from RSSI?

My Set-Up I am sending packets at a specific frequency and with a specific gain from one N-210 USRP to another of the same model. NOTE: I have the transmitting USRP connected to a series of ...
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2answers
2k views

OFDM symbol acquisition block in GNU Radio gives rotating constellation even if there is no carrier offset. How is this possible?

Why does the constellation rotate when using OFDM Symbol Acquisition block in this flow graph below ? The only explanation I could think of would be carrier frequency offset but in this flowgraph ...
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1answer
259 views

Denoising effect in GnuRadio OFDM Serializer block

Why does the OFDM serializer has such a strong denoising effect in the flow graph below ? Is that normal ? The upper constellation is AFTER the OFDM serializer block and the lower is BEFORE the OFDM ...