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Questions tagged [telecommunication]

Use this tag for questions about communications technology and its applications.

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How to to convert LTE SIM data to eSIM (as a carrier)?

I'm running a private 4g LTE network and currently using physical SIM cards. Since I have access to all of the data on the SIM card I'm wondering how I can create an eSIM using that information? Is it ...
R. Rankin's user avatar
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1 answer
28 views

Two-Ray Ground-Reflection Model: Understanding the Difference in Phase Offsets at the Receiver

Currently, I'm trying to understand the Two-Ray Ground-Reflection Model. During my research, I came across the following simplification expressing the received power as follows (taken from Wikipedia): ...
Henerii's user avatar
2 votes
1 answer
107 views

Generating 10 GHz Frequencies with Reasonable Power Requirements

Is it possible to generate 10 GHz frequency RFs at 400 V amplitudes while only using 10-100 W order power? I tried looking up how 10s of GHz frequencies are generated online and found next to nothing ...
Sophia's user avatar
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0 answers
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BLE - connection Point to Point

I'm developing a IoT system, I'm thinking in implementing BLE technology, but I have an unresolved question Description of the system The system implemented will have a "line" topology, ie. ...
Electromosaw's user avatar
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Whats the relation between sectors and 2t2r?

I am quite new in telecommunication domain. I want to know what is the relation between sectors and 2T2R? I know that 2T2R stands for 2 Transmitter, 2 receivers, but what is the connection with the ...
Aled's user avatar
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0 answers
22 views

S-Parameters and Received Power for Implant Antenna

I am simulating an implant antenna using the Ansys HFSS EM simulation tool - the simulation setup looks something like this, with a transmitting (TX) antenna of transmit power $P_{TX}$ and transmit ...
PikaPika's user avatar
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0 answers
24 views

Microwave link budget: rainfall link availability

For starters I'm a python developer and no expert regarding telecommunications and struggling to comprehend the information I came across with for this. I'm trying to design a terrestrial microwave ...
Jay Garcia's user avatar
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2 answers
49 views

Squared telecom parameters

I observe that some telecommunication parameters are squared like noise power is $σ^2=-95\text{ dBm}$, and the amplifier coefficient $η^2=20\text{ dB}$. What is the meaning of the square? Can I remove ...
Mary Dona's user avatar
2 votes
2 answers
1k views

Why do we always use 3.8 x 10^(-3) value as Forward Error Correction (FEC) threshold?

When we want to calculate the bit error rate (BER) for any communication system, why do we always select the 3.8 x 10-3 value as Forward Error Correction (FEC) threshold? Couldn't another value be ...
SH_IQ's user avatar
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1 answer
48 views

What is the best way to enhance an existing LTE signal on a mountain hut?

I'm traveling to a mountain hut in Austria every year which is in the middle of nowhere. If you're lucky you can sometimes get one bar and a weak Long-Term Evolution (LTE) or Edge connection for a few ...
Top Snek's user avatar
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1 answer
114 views

What are the differences between a standing wave ratio meter and a frequency counter?

Im having a hard time understanding what the differences are, I see things on google saying they are both at once and I am really confused.
ClassErased's user avatar
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Faraday's law applied to a coil in an electromagnetic field

According to Faraday's law, we have the law: where "e" is the electromotive force which is equal to the derivative of the phase of the vector "b" through the surface s of the loop ...
Leonardo Fabbro's user avatar
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35 views

Does channel capacity depend on the valence of the signal to be transmitted?

Say I have a channel with bandwidth W and I want to send data at a rate Rb. Do my SNR requirements vary if I use binary, quaternary, 8-ary or 16-ary signalling scheme? For example let's say I have a ...
InfinityDz's user avatar
0 votes
3 answers
303 views

Rotary Phones vs Pushbutton -- why did we ever have rotary?

I remember when we first got pushbutton phones -- I would say user experience is literally ten times better -- if you used a rotary phone extensively as part of your job, you would rapidly develop a ...
releseabe's user avatar
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117 views

How can a screen be projected on a transparent glass?

I am building something similar to Google Glasses although not exactly that. I am trying to find a way to project my 0.96inch OLED on a glass, but it can't block the front view. What I tried to do is ...
Abrar's user avatar
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2 answers
70 views

Demodulation of AM signals in radio broadcast systems

I have a question regarding the demodulation of AM signals in radio systems (like car radio). I know that in order to send the audio signal from the broadcasting station to users we need first to AM ...
Daniel Cohen's user avatar
2 votes
1 answer
113 views

Does anybody know what this symbol is?

The last couple of weeks, I've been noticing this (wifi like) symbol next to some of my contacts in my Android phone. The symbol I am interested about is in the red circle that has the outline of the ...
NMech's user avatar
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Double Stub Matching Impedance

I'm trying to understand the double stub matching impedance using Smith Chart. Here is the diagram for the double stub impedance: The impedance on the right has to appear purely resistive. So ...
Orpheus's user avatar
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1 vote
0 answers
47 views

Calculate the temperature stability of wavelength demultiplexer

Hi ive been given this question: A wavelength demultiplexer (DMUX) used in a DWDM communication system has a channel spacing of 100 GHz. The operating pass band of each channel is 50 GHz. The ...
jilkie's user avatar
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0 answers
43 views

Choosing a Project

Sorry if there’s any spelling mistake... I don't know if this is the proper place to ask, but I guess if it isn't, I'll get notified. Anyway, if it isn't, I apologize. I’m a telecommunications ...
Gustavo Lozada's user avatar
0 votes
1 answer
69 views

How to make a wireless modem using a normal Wi-Fi router and a 4g usb modem

I have a normal TP link (Model: TL-WR841N) router and an USB 4g modem. But the WIFI router does not have any USB port. I want to connect the USB modem with the router, want to share internet ...
Shakib's user avatar
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1 answer
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Ethernet extender kit claims to send data through power cables - Is this correct?

I own an ethernet extender kit which has two devices connected to mains. Its data sheet claims that the device "your homes electrical wiring to extend your broadband network anywhere in the house&...
Krish's user avatar
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1 vote
1 answer
100 views

When recording VHS tapes from analogue TV back in the day, was the "Teletext" data also recorded?

Ever since I was a kid in the 1990s, I've been wondering about this. I have never been able to verify/test it in a conclusive manner. It may be almost forgotten now, but in those days, each TV channel ...
Rondall H.'s user avatar
1 vote
0 answers
157 views

Mesh Wifi Router Network for a Small Village

I was wondering if its possible to create mesh network of WiFi for relatively large area? I am talking about the size of small village (~20km2). The idea is to use centralized connectivity with enough ...
gijoe's user avatar
  • 83
-1 votes
2 answers
55 views

Why radio communication was limited to military use and did not become popular with general public like cell phones have become today? [closed]

Why did no private company or government try to bring radio communications to general public like we have cell phone today? What were the hurdles and challenges?
Naveed's user avatar
  • 99
7 votes
1 answer
345 views

How were the tones for DTMF chosen?

In my limited engineering knowledge, and limited research skills, I couldn't find a complete answer for the reasoning behind the chosen tones for DTMF. I did find a hint that said something about ...
natebot13's user avatar
1 vote
0 answers
12 views

Monitoring Connectivity on ZigBee

I am trying to figure out some ways in which a ZigBee network can be monitored. As is the case in any network, here we have a central coordinator and several slaves joined, however, there seems to be ...
user27435's user avatar
2 votes
3 answers
839 views

Bandwidth vs Capacity

Two questions on wireless transmission, packed into one. First: I am confused about the meaning of the term 'Bandwidth' in a wireless transmission environment. The two most common definitions I could ...
user27435's user avatar
1 vote
1 answer
55 views

How progressive scan televisions works in depth?

I'm trying to understand in depth the behavior of progressive scan TV monitors (LCD/LED - Digital Television). From what we already know, the tv's screen scans the image row by row (as rolling shutter ...
CristoJV's user avatar
  • 111
1 vote
2 answers
65 views

With the "plain old telephone system", would two neighbors be able to call each other privately?

Suppose that Joe and Sue are neighbors out on the country. The year is 1950. But it could also be 1975. Or even 1999. Even though they live next to each other, and can see each other through the ...
Gregg Eckelberry's user avatar
-1 votes
1 answer
82 views

How is it possible that an *undertaker* invented the automatic telephone exchange? And as early as in 1888?

Strowger, an undertaker, was motivated to invent an automatic telephone exchange after having difficulties with the local telephone operators, one of whom was the wife of a competitor. He was said ...
Tamjid Maerten's user avatar
1 vote
3 answers
178 views

Would not a telephone call (from the late 1950s) auto-disconnect if one of the parties "closes the handle"?

In the Alfred Hitchcock Presents episode "Togeather", S03E15, at 17:17, you see a drunk man leaving a telephone without putting it on its handle, with the person he was talking to begging him to "...
Shaindel's user avatar
1 vote
0 answers
11 views

how to implement an encoder in matlab

How can I encode a quantized vector in matlab ? This is a part of a problem where I am asked to implement a communication block using matlab.
user23713's user avatar
1 vote
1 answer
39 views

Fourier serie signal approximation

I have to approximate the red function with Fourier harmonics. I am calculating complex Ck the following way. I am not sure what to put for period - T (6 or 2pi or what?). What integral limits to ...
Dykow's user avatar
  • 11
1 vote
0 answers
171 views

LTE to 3G IRAT Handrover: What happens afterward

Let's say that there has been a handover from LTE to 3G of a particular UE. Once the handover is complete, the MME is no longer required to maintain the sessions/bearers that has been established for ...
Romeo Sierra's user avatar
1 vote
1 answer
103 views

Electronic symboles in datasheets

I found these symbols in a electronic datasheet.. Are these all logic gates? or another?
ISURU THIWANKA's user avatar
1 vote
0 answers
362 views

Is it better ASTRA 19.2°E or 28°, in central continental europe?

I'm trying to tune my satellite receiver, particularly to receive the signals of the Astra satellites, which are ASTRA 19.2E and ASTRA 2 at 28º East. Looking at the picture the signal from ASTRA 28 ...
Michaelangelo Meucci's user avatar
1 vote
0 answers
260 views

Spectral Efficiency of FDD, TDD, and FD

I would like to show at high level that, in principle, the spectral efficiency (SE) of frequency division duplex (FDD) equals the SE of time division duplex (TDD) and both of them are half the SE of ...
Kotsos's user avatar
  • 111
2 votes
0 answers
41 views

Non Orthogonal Multiple Acess and Channel Quality Indicator

As we know in a 4G network, the LTE give us a correlation about the SNR of user and the data rate of the user. This correlation is usually a table called Channel Quality Indicator (CQI) which is found ...
user avatar
1 vote
0 answers
32 views

Mobile Frequency and Carrier Frequency not Matching

I am using a Google Nexus 6 Mobile in India with Airtel as Network Provider. Recently Airtel has upgraded their Network to 2300 Mhz 4G. Whereas Google Nexus 6 Operates on Band 3 (1800Mhz) LTE. When ...
Mitesh Manani's user avatar
2 votes
1 answer
85 views

What is the purpose of colour code for telephone wires?

I'm trying to understand how telephone wires work. I've stumbled upon this kind of identification method with colours. I can't manage to understand the reasons why is used and if it's still common to ...
Gabriele Scarlatti's user avatar
1 vote
1 answer
98 views

Material to absorb very low frequency radio

Is there any material that will absorb very low frequency radio light? I know that stealth aircraft use radar absorbant materials in their design that absorb radio light best at certain frequencies, ...
Hypnos Stratagem's user avatar
1 vote
1 answer
43 views

why can't remove the Image frequency using a band-pass filter?

why can't remove the Image frequency using a band-pass filter? I've been asked to search for the reason why we can't use BPF (band-pass filter) in order to remove the effects of the Image frequency? I'...
parsa ghaderi's user avatar
2 votes
0 answers
177 views

Negative transmit power in dBm

I am calculating the transmit power for $K$ single antenna IoT devices in an Indoor scenario. The receiver has 64 antennas. I am trying to minimize the transmit sum-power, i.e., $\sum_k p_k$, where $...
Chandan Pradhan's user avatar
1 vote
0 answers
22 views

Modeling of a Wireless Channel with known BER

I have to model through software a wireless (my choice: 3g,4g, 802.11...) channel with given Bit Error Rate. I'm searching some distributions, I'm reading tons of papers but I can't find how to ...
Andrean's user avatar
  • 111
0 votes
1 answer
58 views

ADSL near end crosstalk (NEXT)

During a lecture my teacher told me that the UPSTREAM in ADSL is very much affected from near end crosstalk due to DOWNSTREAM, while DOWNSTREAM is not affected by this phenomena. This lead to the ...
Giacomo Pellicci's user avatar
2 votes
1 answer
227 views

What is tonal masking?

I have checked the definition of tonal masking on Wikipedia and google but I saw the definition of sound masking and auditory masking. Auditory masking Sound masking But I want to know what ...
Nzui Manto's user avatar
2 votes
1 answer
64 views

Propagation loss in USRP antenna

Problem I have two USRP antennas close to each other. I know that signal strength on the receiving end has to be at least -80 dBm. Both antennas have 2 dBi of gain. I want to compute what ...
Tuki's user avatar
  • 121
0 votes
3 answers
275 views

Tethered Balloons vs Towers for Wireless Communication

If we use tethered balloons (aerostats) with wireless gateways fitted on them (let's say for Cellular or LPWAN communication), they can provide much more coverage owing to the height they can reach (e....
shivams's user avatar
  • 111
1 vote
0 answers
62 views

What are the strengths and limitations of the antenna design of the Montjuïc Communications Tower?

The Montjuïc antenna is an interesting design for an antenna. I presume the design is principally an antenna, but perhaps it is not? If the ring + mast is an antenna, how does the ring work to ...
New Alexandria's user avatar