Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [software-defined-radio]

The tag has no usage guidance.

1
vote
3answers
186 views

How can I record RF?

For audio I can use just sound card, plus OS api to record any signal from 20 hz (below that's blocked via capacitor) to 96khz(that's half of max samplerate). But what if I just want to go higher? As ...
0
votes
0answers
67 views

Automate sequence of different remote control presses

I've got the following setup I would like to automate: Press button A on a remote to turn the alarm system off Press button A on a remote to open the garage door Press button A on a remote to close ...
0
votes
0answers
70 views

Manchster Decoding when symbol are misaligned

Have this problem: I can manually easily decode this using Manchester: It will be 01010100001 etc However how should I decode this: It should be a start sequence code. However on the first ...
0
votes
0answers
83 views

Keyfob decode using GNU Radio Companion

Found this project to decode Hella Keyfobs https://github.com/bastibl/gr-keyfob Try to decode mine, but somehow the signal is way different from the one from the above Repo. From the repo: Mine: ...
0
votes
0answers
25 views

How to resolve error in sending user data to USRP's SDRu transmitter function?

I'm trying to send user defined data over USRP board using SDRu Simulink blocks available. Following is the block diagram of my model: Basically right now I'm trying to use the USRP board as a ...
0
votes
1answer
187 views

Effects of impedance mismatch on RF signals from antenna

I'm building an antenna array that operates at high frequencies (around 2 GHz). I want to use a SDR dongle that has a 75 ohm input impedance as receiver, I've also bought the coax cable, a 4 way ...
3
votes
2answers
564 views

Expected peak-to-peak output voltage of satellite LNB

Anyone know what the output voltage of a typical DirecTV LNB might be? I've converted an old dish to be a backyard radio telescope and I'm hoping to record output levels with a USB oscilloscope, as I ...
-4
votes
1answer
80 views

SDR usage and safety [closed]

I am considering to purchase an RTL SDR dongle for some hobby purposes, but I have some questions regarding health safety and instructions, if any, that are to be adopted. This is the dongle that I'm ...
-2
votes
1answer
184 views

Software defined cell-phone detection [closed]

I want to at least detect devices that are using 2G, UMTS or LTE. What would be the basic stuff, in terms of hardware and software, for that? I assume gnuradio or some Universal Software Radio ...
0
votes
1answer
668 views

Interpreting IQ Data (as hex) from an RTL-SDR/Hack-RF

I am wondering if someone can shed some light on how to meaningfully interpret I/Q data that is produced from an RTl-SDR dongle (RTL2832U) using the Osmocom RTL-SDR library. I have used I/Q data ...
-1
votes
1answer
66 views

Equivalent circuit for a radio power source (USRP)

I have a radio signal source (USRP N210 with a WBX daughterboard) that can supply a maximum power of 100mW. I am designing a power amplifier for it and I would like to simulate the radio signal source ...
1
vote
1answer
352 views

Maintaining phase continuity of LO when switching from Tx to Rx mode

I am building a two-way communication setup based on software defined radios. Setup: The Tx needs to send a sinusoid to the Rx, and the Rx - after some processing - sends its own sinusoid in return. ...
0
votes
2answers
79 views

Differential QPSK receiver

The communications channel between a QPSK transmitter and receiver can introduce an arbitrary phase change. For this reason, differential QPSK is used. Differential QPSK seeks to solve the phase ...
-2
votes
1answer
240 views

Simplest FM Radio Spectrum Capture Hardware Without Demodulation [closed]

I am trying to build a FM receiver circuit with simplest elements, transistors, capacitors (an op-amp such as LM 741 would be fine too) for analysis purposes (not real-time radio). The circuit should ...
1
vote
3answers
1k views

Where does SDR IQ data come from?

I have never really done much RF design before, and am looking into getting an SDR and messing around with it. I have been doing some research into how they work, and havr found that IQ modulation and ...
0
votes
1answer
219 views

Determining the bit rate on a real-time USRP implementation

I'm transmitting a 16-QAM signal using an NI 2920 USRP. Here is a snapshot of the front panel that is seen (on LabVIEW) - I'm trying to figure out the bit rate from the given details. The symbol rate ...
10
votes
4answers
8k views

How does an AM radio filter out only the desired frequency?

I understand that electromagnetic waves in the air induce an alternating current in the antenna. I also understand how, once you filter the signal to obtain the desired frequency, you can get the ...
0
votes
1answer
76 views

Television Radio Module or Circuit

I want to listen TV channels without display (terrestrial) just like FM Radio channels. There are lots of FM receiver circuits on the web but I couldn't find for TV channels. Is such a thing possbile ...
1
vote
1answer
125 views

Signal recovery in Frequency domain?

I am writing a MATLAB program in which I am doing OFDM symbol transmission through Fading channel: ...
1
vote
1answer
394 views

Forwarding a signal from RX to TX using a USRP with FPGA

This is a LabVIEW (Software) FPGA (Hardware) question so I don't know whether I should post here or on Stack Overflow. I have a USRP-2953R and I want to achieve a very simple project. I want to read ...
1
vote
1answer
439 views

Making my own radio transmitter

So I have recently been interested in Radio electronics, and I have been looking around to buy a HAM radio transmitter,but they tend to be very expensive (and you learn nothing by just buying it). So ...
2
votes
1answer
876 views

RF Harmonics and Spectrum Analysers

Please forgive the long question. I have split it into 2 parts. I am very confused about how harmonic suppression is measured in RF system (in my case, ham radios). I have picked up a couple of the ...
2
votes
2answers
2k views

Can I amplify high frequency signal?

I have found this awesome Raspberry PI FM transmitter project. It uses RPi GPIO pin to simulate FM signal. After some filtering to smoothen it, this could act like a real transmitter. But at this ...
2
votes
2answers
3k views

Down-Conversion of RF signal

I have a basic question about down-conversion of RF-signals. The ideal scenario is described as follows. Given a RF-signal (coming from an antenna), i.e., a real-valued function x(t), and given a ...
0
votes
1answer
812 views

What are the LE (latch enable) and the CLK (serial Clock) pins on the TQM8M9077?

I'm new here, so bear with me. I'm working on a sdr board for a raspberry pi and I have selected the TQM8M9077 as my DVGA. While looking at its datasheet and I came upon a few questions. What are the ...
1
vote
1answer
195 views

Listening to Atmospheric noise

I want to pick up atmospheric noise at 7 MHz and multiply that up to 400 some odd MHz. The reason to do this is I have a USB receiver for digital television that I would like to open in windows and ...
4
votes
3answers
672 views

Can I/Q signals from two perpendicular antennas be simplified to any less than 4 signals?

Say I have two magnetic loop antennas oriented perpendicularly, such that one antenna has a null facing east/west, while the other has the null facing north/south. Each of these antennas is connected ...
2
votes
2answers
198 views

Two signals alternately on the left and right of a frequency

I was listening to the WebSDR of Twente University, just outside the amateur band, and saw these signals. The x axis is frequency in kilohertz, the y axis is time, where the whole axis shown is about ...
3
votes
4answers
1k views

Why no 24 Bit Software Defined Radios?

I have researched and I understand why there are no 32 bit Analog to Digital converters; it is because basically when you go beyond 24 bit, you begin to pick up on the noise generated from the ...
0
votes
2answers
164 views

OOC coding in Wireless Radio Mesh Network

Can anyone explain me whether OOC (i.e. optical orthogonal coding) works in radio frequency? Or only for optical/laser technology?
31
votes
4answers
41k views

Can somebody explain what IQ (quadrature) means in terms of SDR?

This is a bit of a basic question, but I am having trouble understanding why a signal needs to be broken up into I and Q components to be useful for software-defined radio (SDR). I understand that ...
3
votes
1answer
327 views

Implementation ideas for software defined radios

I find Software defined radios interesting, and was searching for ways to learn about it. One way is getting your feet wet with devices like USRP products. However, USRPs are rather expensive. What ...
2
votes
1answer
6k views

Oscilloscope/Function Generator with GnuRadio (using very cheap hardware)

I was just getting started with RF signal processing, and I was very interested in being able to make an oscilloscope and function generator work in real time with python. Essentially, I would like ...
0
votes
3answers
2k views

SFF SDR: How to implement a simply program in the FPGA

Although this a very specific question, I think someone of this site could give interesting information. I am using a SFF SDR of Lyrtech I am trying to generate a .bit file using a .vhd file and a ....