Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [sdr]

Software Defined Radio is a technology for doing radio signal synthesis and demodulation/analysis using software.

Software Defined Radio is a technology which abstracts the hardware functionality of a radio transmitter or receiver (for example, FM radio) into software.

In an SDR receiver, the hardware simply samples raw RF signal and provides the data to software that analyzes and demodulates it.

103 questions
20
votes
2 answers

"56k modem" found in VHF band

While scanning the VHF spectrum with a SDR USB dongle, I found something that sounded like an old 56k modem (at around 160MHz, FM modulation, Europe region). After some research, I found out that is relatively common to broadcast digital messages…
Dino
  • 359
  • 1
  • 6
15
votes
4 answers

Receive several fm-radio stations at the same time (~10-20 MHz wide summary at 90MHz radiofrequency)

What is a cheap way to receive and record on PC several (tens) of fm-radios (public, e.g. news, music, etc)? Such radios uses frequencies like 90.4 MHz or 102.7 MHz, sends a stereo (sometimes with digital text subchannel). If I want to record tens…
osgx
  • 665
  • 1
  • 10
  • 19
11
votes
1 answer

What could this signal at 119.9 MHz be?

I had some fun with an RTL-SDR dongle, and I noticed this weird signal with no noticeable pattern at 119.9 MHz. What's even weirder is that the signal is symmetrical. What might this be? Or is this simply a hardware error? EDIT: This picture is…
technical_difficulty
  • 219
  • 1
  • 8
9
votes
1 answer

Impedance of differential inputs on AD converters

I'm currently trying to attach a rather fast ADC/DAC-converter chip to an FPGA to receive and transmit RF in the future, but getting the converter to run and attaching a signal generator and an oscilloscope for testing is my main goal right now. I'm…
Andy
  • 93
  • 5
8
votes
2 answers

What RF attentuator would be used for the HackRF?

Background info: The HackRF is an SDR Radio capable of receiving and transmitting frequencies from 10MHz to 6GHz. Michael Ossmann, the creator of the HackRF, states in his wiki that: The maximum RX power of HackRF One is -5 dBm. Exceeding -5 dBm…
HelpingHand
  • 183
  • 1
  • 6
7
votes
3 answers

Is information lost when you downconvert an RF frequency?

I am trying to work out what happens when you downconvert an RF signal, such as what happens in an SDR device when tuning to a given frequency. For example if a device using a Zero-IF is tuned to 399MHz, then whatever signal you see at 400MHz will…
Malvineous
  • 1,649
  • 1
  • 15
  • 27
7
votes
2 answers

Bandwidth vs sample rate in SDR

In software defined radio (SDR) I often see sample rate and bandwidth interchanged or maybe I'm misunderstanding... If an sdr can sample a 2 MHz wide slice of rf spectrum does that imply it would be sampling at 2 million samples per second (2M S/s)?…
Brad Hein
  • 1,042
  • 3
  • 13
  • 18
6
votes
2 answers

limit duration 1pps signal

As a beginner in electronics, I would appreciate very much to get some input from you folks for my project, so I can decide in what direction to point my nose :) What would I like to do? I would like to superimpose a 1PPS signal coming from a GPS…
user2950459
  • 71
  • 1
5
votes
2 answers

How would I go about analyzing this SDR-captured 300 MHz radio signal?

I am attempting to reverse engineer the signal from a 300 MHz garage signal as a learning experience rather than an exercise in efficiency. My intent is to purchase a 300 MHz broadcaster IC and connect it with a microcontroller so that I can have a…
stormist
  • 654
  • 1
  • 11
  • 20
5
votes
1 answer

Designing an optimal BPSK and/or QPSK transciever in SDR

I'm currently working on writing firmware for the modem on a cube satellite for my university's satellite team. My primary goal is to implement the data uplink & downlink. The RF system, completed before I arrived, receives on the 2m band and…
Synchrondyne
  • 3,764
  • 21
  • 31
4
votes
2 answers

Homemade GPS Receiver: Cascading LNAs and Band-Pass Filters?

Over the last couple of months, I developed a software-defined GPS receiver. Unfortunately, it's not very sensitive, and can only detect very strong satellite signals. For the RF front-end, I am using a cheap active GPS antenna and an AirSpy SDR, as…
Manuel Menzella
  • 123
  • 6
4
votes
2 answers

Safe to connect SDR to home Cable?

I have an SDR (RTL2832u) that connects to an antenna and can receive over the air just fine. I'm wondering if the signal of a home cable connection would be too strong to connect to the SDR input or is it safe? Say for example my home cable modem…
Brad Hein
  • 1,042
  • 3
  • 13
  • 18
4
votes
0 answers

bearing ambiguity resolve (direction finding) for multiple sources

I am working on wideband direction finding algorithms for passive sensors. I started with Music algorithm. For practical reasons, the spacing can not be maintained lambda/2. For greater antenna spacing, grating lobes appear. I found some…
Sanjoy Basak
  • 41
  • 1
3
votes
2 answers

What sampling rate is needed for demodulating and decoding GPS signal data?

I just got a software-defined radio (SDR) and am trying to record GPS frequency (L1 1575.42 MHz). I understand that GPS is modulated using Binary Phase Shift Keying. I also read about the Nyquist rate which says that I would need to sample the…
Ryan
  • 131
  • 2
3
votes
2 answers

SDR pcb design guide

I am searching for any type of guides for pcb design for SDR (software defined radio) application without luck. I am planning to design pcb board with Zynq-7000 and AD9364 onboard. Any recommendation and useful links? Thanks.
user3583807
  • 375
  • 5
  • 12
1
2 3 4 5 6 7