Questions tagged [software-defined-radio]
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199
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Triangulation by phase delay basic requirements
I'm trying to identify the relevant specifications/calculations for building a system (at least theoretically) to accurately triangulate the position of a 915MHz CW transmitter to within 1cm. I have ...
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Transmitting data with QPSK using an SDR
My question assumes that I want to transmit some data using QPSK using and SDR.
The SDR will be fed with IQ data and this will transmitted at a sample rate Fs and be up converted to a carrier ...
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USRP N210 B & F Lights
During setup of a USRP N210 on MATLAB's Communications Toolbox Support Package for USRP Radio, the initial test failed on "Receive the signal and verify the frequency of the tone" field. ...
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USRP N210 Connection Issues on Ubuntu 22.04 VirtualBox VM
I am running into consistent connection issues when trying to run a USRP N210 on a VirtualBox Ubuntu 22.04 VM. I built uhd from source on the ettus page, configured a static IP address in Ubuntu, ...
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Complex samples in OFDM signal, after fft-block at the receiver, have rotating amplitude towards zero even after phase correction
First of all, please consider my lack of experience/background in real time transmission using SDR especially if my explanation was expressed technically well.enter image description here
I have ...
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OFDM complex symbols have dynamic phase shift after the fft-block & before the BPSK demodulator at the receiver ,
I have transmitted and received an OFDM-signal using the same ADALM-Pluto-SDR's Tx/Rx Antenna.
I have used BPSK baseband modulation with symbol freq=312.5 KHz, L (length of ifft)=64, fsampling=fsym*L=...
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Why is bandwidth inversely proportional to mulitpath interference?
I have a project related to Signals of Opportunity and during my research on the communication signals that can be used for navigation purpose I saw that as references are given below signals that ...
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DSP library for Software Defined Radio
Can anyone recommend a good C library for SDR? To be more specific I just need a function in C to compute coefficients for CIC compensation filter (I need to do it in real time, so Matlab is not an ...
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Replicating SDR transmitter and receiver (shifting of a quadrature signal)
I am trying to implement an SDR transmitter and receiver based on the description here.
...
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362
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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....
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Does SDR configured with low sample rate automatically averages samples?
This is probably a basic question but I didn't find any answer online.
Suppose we configure a SDR (least say, with a maximum sample rate of 100 Msamples/s) with a low sample rate (e.g. 1 Msample/s).
...
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is it relevent to plot the parcimony of a signal in function of its SDR?
Whilst trying to compare the performance of three blind source separation methods, is it relevent to plot the parcimony of a signal in function of its SDR?
Thank you...
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How to determine the size of DFT bins to implement a bandpass filter with FFTW on SDR
I'm implementing a bandpass filter to isolate the amplitude of a UHF FM signal with a 12.5Khz bandwidth. I'm having difficulty isolating the correct bins and bin spacing, given my DFT to isolate the ...
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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 ...
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113
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Which type of modulation is used in this RF Signal?
I am working on reverse-engineering a few devices, I got some using ASK and FSK but I could not grasp this other one. I am attaching some photos from its captured signal took from URH (Universal Radio ...
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FFT on SDR FM Radio Signal
I recorded a simple FM signal using my SDR (centered at 100.3e6 hz and sample rate of 2.048e6 per second). Without any transformation, I ran an FFT on the signal and it showed a signal with some width ...
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SDR lose samples at high bandwidth (sample rate)
When receiving bandwidth (sample rate) is small (<~28 MHz), the signals are received without any distortion. When I choose high bandwidth (for example 40 MHz), sometimes the signals become ...
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Spectrum analyzer resolution bandwidth (RBW) for LTE signals
I am trying to measure the maximum output power of an SDR transmitting a 20 MHz LTE signal with a spectrum analyzer.
Adjusting the resolution bandwidth (RBW) changes the power spectral density (PSD) ...
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136
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Why don't we need frequency and phase correction in AM and FM?
As far as I understand, double sideband AM with carrier and FM can be demodulated via SDR (Software Defined Radio) without frequency or phase correction. For AM, received signal is
$$r(t) = A(t)\cos(\...
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Generating I Q samlpes for particular sample rate
I want to know what the sample rate of I and Q samples generated for transmission, in the function below from https://github.com/lyusupov/ADSB-Out/blob/master/ADSB_Encoder.py samples are generated ...
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Amplitude modulation in SDR [closed]
I understand the theory of amplitude modulation. However, I couldn't understand it's implementation in SDR, which use IQ data, and I would like to learn
end to end amplitude modulation system in ...
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Is the phase of a IQ point related to the local oscillator frequency?
When considering a direct conversion SDR receiving or emitting architecture, we can "represent" the received or transmitted signal as the sum of two components, the I and Q component.
Each ...
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Choosing the scaling parameters for a modem implementation
I have succesfully modeled a modem using floating-point data and with the following scheme, where the SRRC filter has gain G=6dB.
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How to achieve a DC portable power source with low noise in 400 MHz frequencies
I am working on an SDR composed system that is plugged into a Raspberry Pi board powered by a 5V DC Power bank. The SDR is configured to measure a signal around 400 MHz.
The noise floor measured by ...
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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 ...
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CIR calculation from SDR data: RTL-SDR, bladeRF
We’re developing a prototype using bladeRF and various Python scripts for processing IQ samples.
The system works mainly around 2.4 GHz frequencies: Wi-Fi and Bluetooth.
One of the needed functions is ...
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114
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Biphase/Manchester floating-point decoder based on matched filter
I need to perform soft Viterbi decoding on a Manchester-encoded BPSK/QPSK signals. To that end, I need a floating point Manchester decoder. Most of the implementations I have seen operate on hard bits....
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170
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SDR - Manual FFT PSD vs pylab PSD
I am trying to calculate the power spectral density step by step using numpy FFT and comparing it to the PSD calculated by pylab PSD. Difference b/w plots of both methods can be visualized from in ...
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142
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oQPSK symbol synchronization
I'm validating a C++ oQPSK receiver. The 5Mbps oQPSK signal is generated by a satellite emulator. The receiver structure goes as follows:
SDR --> AGC --> Costa's Loop --> Delay --> ...
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How to demodulate FM I/Q output from SDR#
Using SDR#, I saved the baseband I+jQ signal centered about a commercial FM station to a *.wav file. I want to write python code to demodulate this signal. I know that SDR# can read in that file and ...
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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 ...
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gnuradio , SDR usrpx300
I use usrp x300 SDR.
I'm confused about Bandwidth and sample_rate. How do I calculate
them? is ...
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Interference between 121.5Mhz and 124.5Mhz
I'm new to Software Defined Radios and trying to find out if powerful signals are a cause of my own interference, a poor setup, or just a lot of traffic. I'm using a HackRF One with an ANT500 antenna.
...
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Efficient frequency domain search for reduced number of hypotheses
In CDMA signals (such as GNSS) there are two unknown parameters when one receives the signal, residual carrier frequency and an unknown delay. Assuming the carrier frequency residual is known, what is ...
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How does the sample rate work on an SDR?
How can an SDR, which has a sample rate of about 32MHz record signals with a frequency of 1GHz? Shouldn't the sample rate be at least two times as high as the frequency or am i missing something?
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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 ...
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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 ...
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G3RUH Multiplicative scrambler in C++
I have written and tested a G3RUH (1 + X^12 + X^17) descrambler. It seems to work quite well in an SDR project I'm working on. I'm currently working on a scrambler and I can't get it to work. Below is ...
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Sampling rate for a 200 kHz signal
I'm using a rsp1 to sample the output of an underwater acoustic transducer which has a resonant frequency of 200 kHz (with a 500 Hz bandwidth) . The transmitted signal is a CW pulse which can vary ...
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What a SDR can (and cannot) tell about a received signal's power/energy
I'm rather new to SDR and I'm still wrapping my head around understanding how it functions. I greatly appreciate it if you guys can help me understand what's going on.
From what I've gathered, an SDR ...
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How does SDRs implement anti-aliasing filters, when the sampling rate can be fairly arbitrary?
I was looking at the schematic for the small USRP B205-mini SDR from Ettus. I can't seem to find any switchable analog anti-aliasing filter on the input of the chip, or anything resembling a filter ...
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USRP N210 Main clock rate and The transmission signal Sampling Rate
I am testing the transmission and receiving signal using two USRP N210. The communication setting as follows:
...
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How does under sampling modify the spectrum of a signal in nyquist zones and BW?
I have two conflicting concepts when looking at the spectrum of a analog to digital signal that has been sampled.
The nyquist zones. So any sampling frequency fs will make the spectrum replicate at ...
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Can 2 (coherent) digitizers with input bandwith X be used to digitize a signal of banwidth 2X?
TL;DR:
Can 2 tunable digitizers, each with an instantaneous bandwidth of X MHz and a common clock source, be used to achieve an instantaneous bandwidth of close to 2*X MHz by tuning their central ...
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How to judge the percentage of white noise and color noise when using typical SDR enviroment?
Per this question,I understand different result when noise occurs in time domain and frequency domain.
As to the system,has antenna+upconveter+USRPB210+laptop,...
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SDRs synchronization
I have 3 software defined radios (we can suppose that we have Ettus X310). I need to synchronize them because I need a high level of accuracy.
I know that I can use the Octoclock to synchronize them, ...
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More Efficient Frequency Shift + FIR Decimation
I am dealing with complex IQ data from a software defined radio. I'd like to digitally shift the spectrum by some amount to center an off-center signal, then decimate down to that signal only. ...
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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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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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HackRF setup for capturing GNSS signals
I have a MATLAB script which process IF signals to acquire GPS satellites.
I decided to capture IF signals containing GPS L1 C/A (1575.42 MHz) myself.
What I have:
HackRF
TCXO for HackRF
Active GPS ...
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