Questions tagged [sdr]
Software Defined Radio (SDR) is the implementation of radio receiver, detector and transmitter systems in software, as opposed to analog hardware or application-specific ICs. It usually uses a baseband sampled representation of the RF bandpass signals.
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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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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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24 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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44 views
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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1answer
43 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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3k views
Are Software Defined Radios only Oscilloscopes?
I am wondering if SDRs (software defined radios), e.g. HackRF, RTL-SDR, or USRPs, are, in essence, just oscilloscopes you can plug to a computer to get the data from it. If not, what are the main ...
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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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22 views
Computing Phase Difference Between Two Channels from SDR
I'm trying to compute the phase difference between two channels of a software-defined radio. I'm providing code for two different methods that I'm trying below. In both cases, I'm transmitting a pure ...
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1answer
211 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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1answer
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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23 views
LTEcellSearch on ADALM PLUTO error
Im following the example from Matlab in here https://www.youtube.com/watch?v=lcCWTnmKblE
im trying to capture an LTE frame and decode the cell id, however i get a false PCI and it changes value ...
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2answers
37 views
Real-time FM demod results in clicking and strangely-shaped output
hardware engineer here dipping his toes into software DSP and running into some issues.
I'm attempting to demodulate in realtime a simple narrowband FM signal with samples from an RTL-SDR, and play ...
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49 views
Changing sampling frequency of SDR
Here is the block diagram for RTL-SDR which is taken from Software-Defined Radio Using MATLAB, Simulink, and the RTL-SDR:
I think it well explains the basics of RTL-SDR but I have multiple questions.
...
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32 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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103 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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1answer
84 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 ...
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188 views
SDR : IQ GMSK signal demodulation
I'm trying to develop an application for the demodulation of some GMSK signals transmitted over the air.
I'm using a RTL-SDR which outputs 8 bits IQ samples of the baseband signal.
Here is what I've ...
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1answer
55 views
Digital demodulator (SDR) for receiving legacy analog modulated wave
I understand that in SDR, after the ADC the signal processing is fundamentally based on I/Q modulated waves where any discrete value that can be transmitted corresponds to a symbol which is ...
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9 views
Doubt about sampling rate and spectrum with USRP and gnuradio [duplicate]
I have started working recently with software defined radio (SDR) as well as gnuradio. I have worked with digital signal processing for a while and one feature at one tutorial, which I saw for ...
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315 views
TypeError: primitive_connect() when executing in gnu radio
I'm building the frequency analyzer for RTL-SDR. But having problem in building and executing code.
...
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2answers
61 views
Can I create my IF signal on SDR before bringing data to PC?
I'm relatively new to SDR's and I'm trying to determine what sort of BW I need for my laptop to get the best resolution possible for an FMCW system. I have an X310 Ettus with a UBX160 daughtercard ...
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1answer
27 views
Why I get another spectrum when upconvert an o-qpsk baseband signal with a bladerf compared to a hackrf device?
I have just start working with bladerf instead of former used hackrf hardware and I need to solve a problem. Currently I use the following bladerf hardware, libraries and firmware:
bladerf (2.0 micro ...
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1answer
92 views
Implementation of Overlap Save Filtering with Decimation
I am trying to implement Matlab code which performs FIR filtering with complex bandpass filter using Overlap Save method and perform decimation as well by using different length forward and inverse ...
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1answer
41 views
Code Snippet to Convert ADC Samples to I/Q
I'd like to pull a narrowband signal out of ADC samples, where the ADC rate is much higher than the bandwidth/central frequency of the narrowband signal. I'd like to feed the narrowband signal into a ...
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1answer
82 views
Unstable frequency/phase when using external reference for Ettus B200
I am attempting to do a simple record of a CW, 250MHz signal at the Rx port of an Ettus B200 using an Anritsu MG369 signal generator. I am using the 10 MHz ref signal provided by the SG (output @ ~...
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1answer
264 views
How is the Tx/Rx Gain calculated in USRP?
I know that USRPs are uncalibrated devices. In many exampls you can set the so called Tx or Rx gain (as in the picture below).
Now, I know that this does not correspond to the real power of the ...
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90 views
Need to extract phase of incoming signal, how to find FFT bin of frequency of interest in GNU Radio?
When receiving a higher frequency signal, say 2 GHz, the freq as shown in frequency sink is often off by some amount (1-2 MHz) on the ettus B200. So I can't just assume the location of the signal is ...
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37 views
filter single radio station with sdr [closed]
I want to write a program to filter a single radio station using SDR. Not for any application just a stepping stone to learn. I am going to use C so it is easier for me to see the steps and things ...
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4answers
880 views
What can be done with I/Q data which would otherwise be impossible?
As I understand it, I/Q data is the complex representation of any waveform. It enables us to understand two things at any arbitrary point in time:
The projected amplitude of the waveform.
The ...
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1answer
41 views
How to modulate PSK63 with liquiddsp?
I am trying to implement the BPSK-63 modulator using liuid dsp library.
Here is my code:
...
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101 views
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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1answer
131 views
Detect static in audio with Python
I have a program running in python. It samples the demodulated FM output from an SDR. When there is no transmission, the input to the program is completely static.
How can I go about squelching the ...
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1answer
48 views
SDR Dongle, 2MHz Bandwidth related to Fs but bandwidth range 50-2000 MHz
Having a conceptional issue.
If a SDR dongle has a 2MHz signal bandwidth, but that can be anywhere within the range of 50-2000 MHz, why is the bandwidth only 2 MHz.
The clock must be double the ...
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1answer
62 views
Heterodyne modeling confusion in SDR
I've been reading this lab sheet which explains the signal processing math of the RTL-SDR radio dongle. http://www.eas.uccs.edu/~mwickert/ece4670/lecture_notes/Lab6.pdf In pages 5 and 6, the local ...
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250 views
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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2answers
140 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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1answer
66 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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164 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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1answer
75 views
Max frequency of cosine in SDR
I would like to transmit a 56 MHz real cosine and receive it using SDR with max complex sample rate equals 61.44MSPS and an analog filter with BW = 56MHz (the transceiver is AD9361). Can I do it? How ...
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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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274 views
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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1answer
152 views
Transmitting a 350 MHz signal
I'm currently on an SDR kick and reverse engineering and then emulating all of the remote controls in my house. There are numerous solutions to transmitting signals over 315 or 433 MHz and you can ...
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2answers
358 views
DAC and ADC architecture in SDRs
What are the DAC and ADC architectures in SDRs for inphase and quadrature phase channels?
Do we have separate ADC and DAC for each channel or there is some clever way that they are multiplexed to ...
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1answer
71 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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Possibilities to get the amplitude of a signal at specific frequency from IQ
I'm newbie to the dsp topic and my understanding of math symbols is limited.
So at the moment I'm little bit lost to find the right resources.
I receive an IQ stream from a SDR.
Sample rate: 250k/s
...
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1answer
31 views
Converting PLL Discriminator into Doppler error
I'm writing a GPS receiver SDR software, and I have calculated the PLL discriminator ouptut as atan(Q_Prompt,I_Prompt)
I would like to know the formula that converts the discrminator output to doppler ...
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70 views
PLL in Tracking for GNSS behaviour
I'm doing work on SDR for GNSS and I'm tracking the signals I/Q using PLL.
The calculations for the PLL is done like the following for error estimation:
...
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1answer
1k views
Obtain I/Q Components from a Real Signal On the Fly - Hilbert Transform or Digital Downconversion?
I'm planning to build a data acquisition system for a software-defined radio receiver. Basically, it just uses an ADC which samples an analog signal and send the signal to a processor. And then a ...
