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IQ imbalance correction algorithm for OFDM systems

What are the methods available to calculate and compensate for IQ imbalance using digital samples? What are the methods available: when one is allowed to send known signal and when data send is not ...
user71467's user avatar
0 votes
1 answer
29 views

Magnitude of local oscillator leakage as a function of oscillator frequency

Is there any study on the magnitude of local oscillator leakage as a function of oscillator frequency? If RF input is disabled and there is local oscillator at the mixer, then due to leakage, this ...
user71467's user avatar
2 votes
1 answer
120 views

Is BPSK relevant, or does it even exist, in wireless data transmission?

I ask this question because it seems to me that if pulse shaping has been applied in the transmitter, the signal that is actually transmitted is not phase modulated at all, rather, it is amplitude ...
Drummy's user avatar
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1 vote
0 answers
108 views

Exactly when is pulse shaping applied in the radio transmitter, before or after modulation, and is it applied differently in BPSK, QPSK and 16QAM? [duplicate]

I previously asked at which stage pulse shaping is applied in a WiFI transmitter and my question was closed due to duplication. The answers I was directed to have only served to confuse the issue for ...
Drummy's user avatar
  • 133
1 vote
0 answers
81 views

Processing of Channel State Information from WiFi for Generalizability

For my master's thesis I collected CSI with 4 WiFi network cards (Intel AX210) for three different persons for 102 positions (spaced roughly 30cm apart). The covered area was around 10m x 7m and in ...
binaryBigInt's user avatar
0 votes
1 answer
79 views

How to remove phase shift for a baseband signal given an estimated CFO (Bluetooth)

I am working with Bluetooth specification 5.1 where the advertisement packets can send a constant tone extension (CTE) over the baseband signal to estimate the angle of arrival with an antenna array. ...
Yudop's user avatar
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1 vote
1 answer
355 views

How to calculate phase rotation of I/Q reference samples for Bluetooth Angle of Arrival

I am trying to compensate phase rotation due to carrier frequency offset (CFO) for Bluetooth Low energy (BLE) Angle of Arrival (AoA). In BLE AoA the adv. packets carry a Constante tone extension @...
Yudop's user avatar
  • 15
1 vote
0 answers
81 views

Run FFT on data chunks to reduce peak memory usage

I am trying to run 'wsprd' on a micro-controller for reduced power consumption and fun. 'wsprd' is open-source at https://github.com/pavel-demin/wsprd. This program currently processes ~15 seconds of ...
YGA's user avatar
  • 11
7 votes
4 answers
741 views

Building a data acquisition system to capture raw IQ data

I was planning to build a data acquisition system to capture raw IQ data for a hobby project and the short-term goal is to gain practical experience on RF front ends and ADC's. My background is mostly ...
Farheen Shaik's user avatar
2 votes
1 answer
280 views

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 ...
Amaury's user avatar
  • 21
1 vote
1 answer
182 views

Simulating RF interference (noise) to captured RF signals

I have carried out an approach to clean my RF signal captured in order to perform classification on a set of devices. However, a further extension to this study I aim to achieve is to evaluate the ...
rshah's user avatar
  • 77
4 votes
3 answers
516 views

Undestanding antenna gain applicability

While searching for the info about antenna gain and why it is GAIN I found this interesting example: If the two antennas in the drawing are “welded” together, how much power will be measured at point ...
Vaims's user avatar
  • 63
1 vote
1 answer
189 views

Why do ATSC channels need 6MHz of bandwidth when they're digital?

If I'm understanding it correctly, an ATSC channel is a digital channel that uses 6 megahertz of bandwidth to send 19.38Mbps using 8VSB modulation. For analog broadcasts, that makes sense, but I'm ...
Chris Akridge's user avatar
1 vote
2 answers
139 views

Is digital (discrete) SSB plausible?

Do any examples of digital SSB modulation exist? If not, is it implausible for some reason? The closest thing I can find is something like 8VSB which comes very close to being single sideband. I read ...
Chris_F's user avatar
  • 318
2 votes
1 answer
1k views

Conversion from phase noise to EVM

I have a phase noise specification for a digital QPSK transmitter at 8GHz (symbol rate 50 Mbaud). From that specification I am able to compute the RMS jitter in radians (47 mrad or 934 fs using the ...
ste88tn's user avatar
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1 vote
1 answer
134 views

In wireless communications, is it true to say: The more the range, the more the delay spread?

The general idea which can be drawn by reviewing wireless channel models says that the longer the range/distance, the more the delay spread, even in LOS microwave links. But I really wonder why it is ...
Ali's user avatar
  • 95
3 votes
2 answers
274 views

The transmission distance of a signal

I am no professional in this area so please forgive me if this question is too immature. And thanks in advance for any help and information. I want to know how to calculate the transmission distance ...
user59458's user avatar
1 vote
0 answers
33 views

Why do adjacent cells use different channels?

In chapter 15 of the book Wireless Communications by Andrea Goldsmith, Goldsmith gives a formula for an estimate of the signal-to-interference-ratio for the node on the edge of a cell in a cellular ...
awelkie's user avatar
  • 153
1 vote
1 answer
2k views

How do I determine the carrier frequency of a given AM signal?

I am trying to figure out what the carrier frequency of a signal is given only its discrete-time domain information and the fact that it is a signal on the AM radio frequency band(550 - 1700kHz). Is ...
user58046's user avatar
1 vote
1 answer
750 views

Why is GPS 1575 MHz?

I’ve read that that frequency is a ‘window’ in weather, impacted less by raindrops for example. I otherwise would’ve thought that simply increasing the wavelength would decrease impact. I don’t ...
David's user avatar
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1 vote
1 answer
31 views

Resources for the Basics on Signals and Electromagnetic Waves in the radio frequencies [closed]

What are some good books and videos, to learn about radio waves? For someone (me) who has never studied Math, Physics, or anything people generally consider ‘technical’.
David's user avatar
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0 answers
115 views

Unstable Phase in Channel Impulse Response

I'm using DW1000 UWB radio transceiver and extract its channel impulse response (CIR). The CIR output by the transceiver is the complex baseband CIR. In a static environment, the CIR is a LTI filter ...
jleng's user avatar
  • 1
1 vote
1 answer
250 views

Direct downconversion (IQ downconverter) with ASK modulation-- what kind of Balun do you need?

I have a simple but confused question. I am trying demodulate a 915MHz ASK modulated signal with direct downconversion. So what I am building up is: Antenna --> SAW bandpass filter @915MHz --> ...
j c's user avatar
  • 67
0 votes
1 answer
32 views

Analysis Received Signal at receiver side

I'm trying to understand something which is really confusing me and I made my best to understand it but still confused. If I have transmitted and receiver. Assume I want to transmit S(t) data and ...
Maher's user avatar
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0 votes
0 answers
70 views

OFDM symbols terminology explanation

I've already read and understand what does OFDM mean and what does it stand for and why we use it in our wireless technology today. My question that I didn't understand is what does it mean number of &...
Maher's user avatar
  • 1
0 votes
0 answers
90 views

Forming the estimation manifold for a 2-D beamformer

Given an array of L sensors in a uniform planar array, with known positions in space, I would like to estimate both the angles of arrival and delays from a point source under multipath conditions ...
Thefoilist's user avatar
0 votes
0 answers
46 views

Transceiver for TDoA measurements

Could someone advise me on some module for making the TDoA position system for my research work? I need to have measurements with an accuracy of a few meters. It equals a bandwidth of about 20 MHz. I ...
Victor Legkostup's user avatar
1 vote
0 answers
56 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 ...
meanthatmuchtoyou's user avatar
0 votes
0 answers
24 views

Determine the change of selectivity

I've stacked on solving this problem and can't find an answer in the web, so I decided to ask a question here. There are the problem: Preselector of boadcast receiver contains of one oscillation ...
KhaBeleth's user avatar
3 votes
0 answers
249 views

About discrete time model for wireless channel

I am trying to understand Section 2.2.3 of the book "Fundamentals of wireless communication" by Tse and Viswanath. In this section the authors explain how to go from the continuous time ...
Coniferous's user avatar
6 votes
3 answers
652 views

How a diode-detector affects to Frequency Response?

I have a question related to crystal radio. I can't understand how a crystal detector (diode) shifts the spectrum from the carrier frequency to zero. The antenna receives bunch of signals and the LC ...
John's user avatar
  • 61
1 vote
3 answers
80 views

Can the intelligence message of an FM signal be cross-modulated to another center frequency due to non-linearities?

Can the intelligence message of an FM signal be cross-modulated to a a different frequency by non-linearities, but with the FM modulating message remaining (relatively) intact on the new frequency? ...
Frank's user avatar
  • 169
2 votes
1 answer
666 views

What is the functional difference between DSB and 2SB mixers, and why exactly would 2SB be better for radio astronomy?

The Astronomy SE question 2SB mixer in radio astronomy? asked in 2014 in its entirety: In literature about the instrumentation of radio astronomy, I frequently come across a type of mixer described ...
uhoh's user avatar
  • 231
2 votes
1 answer
689 views

Does Radio Communication Have to Account for the Doppler Effect?

I know that radio communications take place in specific frequency bands, and that the doppler effect can cause shifts in frequency when there is relative motion between the source and destination ...
Matthew Inbox's user avatar
1 vote
1 answer
1k views

Difference between slow, medium, fast AGC

In digital receivers, at the RF level (not audio), I often read about "slow AGC" and "fast AGC", and sometimes even "medium AGC" (but I think the latter is for audio). From my understanding, the slow ...
Signal's user avatar
  • 117
1 vote
1 answer
157 views

RF Downconversion using Heterodyne Principle

after a RF down-conversion using heterodyning principle, will there be an information loss? If we translate to a fixed IF frequency, is there is an intuitive way of explain that the information can be ...
radar101's user avatar
1 vote
3 answers
132 views

Why does altering path length in radio transmission alter the phase of the received signal?

I do have a very naive yet bothering question: Assume I send a sinusoid signal \begin{equation} A*cos(2\pi ft+ \phi_0) \end{equation} over a radio channel. Assume there is only a LOS-path for each ...
fl0ta'''s user avatar
  • 49
0 votes
4 answers
682 views

Why is In-phase Quadrature sampling not used to record and store digital audio?

I/Q is a standard method to sample radio frequency and its use is even seen in some non radio signals like sonar. But it seems that it is not used to sample acoustic frequencies. What property of ...
medbot's user avatar
  • 3
0 votes
1 answer
65 views

5G NR Network Collision Avoidance

I'm looking for a technical explanation or a specification that explains exactly how 5G NR collision avoidance will work. I was watching a talk from the Mobile World Conference in Shanghai two years ...
Shrout1's user avatar
  • 103
0 votes
1 answer
104 views

Wireless Channel Multiplicative Model

Let's assume a SISO channel in the equivalent baseband, the standard channel model (discrete) is: \begin{align} y(k) = h(k)x(k) + z(k) \tag1 \end{align} Where $y(k)$ is the detected signal, $h(k)$ ...
ulfgar's user avatar
  • 28
4 votes
3 answers
899 views

Why is the carrier suppressed by AM-DSB-SC modulation?

Lets say I have a message that is a sine wave at 1KHz. As I understand it, I can perform amplitude modulation by multiplying this signal with a carrier, lets say 10KHz, and this process is essentially ...
Chris_F's user avatar
  • 318
0 votes
0 answers
73 views

modelling radar system for image generation

I am trying to find or derive some model for radar using python and blender which should hopefully create a simulation of what a radar image of the blender environment would look like. I have been ...
O. M.W.'s user avatar
2 votes
1 answer
178 views

SDR spectrum anomalies

Is it normal to see periodic peaks going from 48.75 - 90 MHz? Also i was checking on my SDR dongle once and the whole band was raised above background offset for like a whole 50 MHz bandwidth and then ...
ChemEng's user avatar
  • 121
1 vote
0 answers
156 views

What is DAB modulation in signal generators?

I am using R&S signal generator and for generating a DAB signal there is an option for mentioning the modulation level in %. For example, we can generate DAB modulation 50% . I can understand that ...
newbie's user avatar
  • 11
1 vote
0 answers
400 views

How to setup filters to catch 4FSK deviations

I'm trying to demodulate a radio signal from Motorol DP4801 (MOTOTRBO) that follows DMR specification. I'm receiving the signal by using HackRF with the rate sample 1 MHz. The radio uses frequency ...
flipback's user avatar
  • 111
0 votes
2 answers
90 views

What do you mean by radio sensing a channel?

I am slowly getting into the field of wireless communications, in particular with WiFi based communications. 802.11 MAC mentions that A station wishing to transmit first listens to the medium ...
Jani 's user avatar
0 votes
0 answers
51 views

Will LoRa work from Earth to the Stratosphere

I'm unsure if this is the most suitable exchange however I thought it seemed most fitting personally, please correct me if I'm wrong. (I got redirected to here from the Network Engineering Exchange). ...
Explorex's user avatar
  • 101
1 vote
0 answers
49 views

Help in identifying low speed image transmission protocol over RF

In the seventies I worked for Muirhead on press fax machines that used to transmit pictures over radio and landline as I recall two FM systems were used a carrier 800 Hz modulated +- 150 Hz and 1900Hz ...
syhprum's user avatar
  • 11
0 votes
1 answer
773 views

Why do IQ Impairements, Quadrature Skew and DC offset have these geometric effects on the constellation?

I'm studying telecommunications, and would like to be sure to understand the maths behind these effects. For IQ Imbalance and DC offset, it seems pretty clear why we observe a rectangle shape or a ...
ISMAIL S.'s user avatar
0 votes
1 answer
268 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 ...
rider99's user avatar