Questions tagged [telecommunication]

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

Filter by
Sorted by
Tagged with
0
votes
0answers
41 views

Purpose of TV Towers at Present [closed]

We know that different communication towers exist around the world(e.g. Tokyo Tower). They are not only used as a TV tower but for radios and touristy purpose too. This is the age of dish antenna, ...
-1
votes
2answers
33 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?
5
votes
1answer
41 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 ...
1
vote
0answers
8 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 ...
2
votes
3answers
60 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 ...
1
vote
1answer
33 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 ...
1
vote
2answers
46 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 ...
-1
votes
1answer
41 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 ...
2
votes
3answers
106 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 "...
0
votes
0answers
15 views

Cell phone booster for multiple buildings

Our company has a small remote site which includes three buildings, each less than 5k sqft, in a line. All three have poor to non-existent cellphone reception within the buildings themselves and only ...
0
votes
0answers
6 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.
2
votes
1answer
33 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 ...
1
vote
0answers
35 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 ...
1
vote
1answer
51 views

Electronic symboles in datasheets

I found these symbols in a electronic datasheet.. Are these all logic gates? or another?
1
vote
0answers
47 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 ...
1
vote
0answers
63 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 ...
2
votes
0answers
39 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 ...
2
votes
0answers
29 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 ...
2
votes
1answer
55 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 ...
1
vote
1answer
59 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, ...
1
vote
1answer
27 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'...
2
votes
0answers
76 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 $...
1
vote
0answers
17 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 ...
0
votes
1answer
35 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 ...
1
vote
1answer
85 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 ...
2
votes
1answer
37 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 ...
1
vote
2answers
88 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....
1
vote
0answers
46 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 ...
-2
votes
1answer
179 views

Why is Morse code used in satellite communication compared to ASCII encoding

My knowledge about methods of transmission of data is limited, but I believe that communication between transmitters and receivers often uses Morse code to send information. If say, a satellite ...
1
vote
0answers
40 views

How EnB will inform to UE about incoming call in RRC connected state in LTE?

Generally if UE is in RRC Idle state, ENB will inform to ...
1
vote
1answer
44 views

A radar that is not an OTH detection distance

Let's say that we have a radar that is not an OTH on a boat, and it is placed 30 meters above the ground. Is there a way for it to detect an offshore platform 152 kilometers away from it, since the ...
2
votes
0answers
47 views

How can the Microsoft and the Facebook Fibers reach 160 Tbps between Virginia and Bilbao?

According to this article, Microsoft and Facebook have completed a 160 terabits cross-Atlantic cable. Based on my calculations, this doesn't seem probable, so what did I miss in my calculation? The ...
1
vote
2answers
86 views

How do I get data from my Hardware to server or so? [closed]

Brief I am actually of 17 not even in college but I have dream for making my project/dream/aspiration/or So to come true so I am thinking of making a device that performs a function say like ...
1
vote
0answers
59 views

Can a casio fx series do this operation?

"Calculators stackexchange" doesn't exist, so I guessed this would be the right place to ask. Can a calculator solve $-0.2 \cdot e^{-0.06-4.2i}$? Or any $e$ to a complex for that matter. I've been ...
3
votes
2answers
5k views

Why downlink frequency is greater than uplink frequency in mobile communications?

Generally, downlink freq. > uplink freq. in mobile communications. I was able to gather some answers as to why is so. But my seniors (in my company) seem not to be satisfied with the below answers. ...
1
vote
1answer
40 views

Why only the spectrum range of radio waves can be reflected from atmospheric layers while higher ranges (Infrared-Visible Light-Ultraviolet) can't?

From communication prospective why can't higher frequency ranges be reflected from atmospheric layers and what is the effect of parameters (like temperature, pressure, etc) of the atmospheric layer on ...
0
votes
2answers
417 views

Why does India have more than 1 MCC (Mobile Country Code)? [closed]

I was checking the list of MCC (Mobile Country Codes) on Wikipedia and found that India has two MCC: 404 and 405. 404 contains only GSM/UMTS/LTE operator bands and 405 contains both GSM/UMTS/LTE and ...
1
vote
0answers
29 views

How does the demapping/demultiplexing of transport channels to logical channels work?

I am trying to model WCDMA MAC, but I cannot figure out how to demultiplex HS-DSCH unto DCCH, DTCH. Also, since I am using E-DCH/HS-DSCH transport channel scheme, how does the data of DCCH and DTCH ...
-1
votes
1answer
43 views

Sending SMS using car horn [closed]

If you've been watching Bones series, there is an episode in which Bones and Hodgins were trapped beneath the ground, and they managed to send an SMS by wiring the phone to the car honk. Is this ...
0
votes
1answer
107 views

How does 4G know the reception of a voice call?

I know that the 4G network is only for data and doesn't support voice calls. Most of phones switch to 2G/3G when receiving a voice call. But my problem is how does the phone gets to know about the ...
2
votes
1answer
118 views

Why is WiFi increasing frequency?

WiFi at 60 GHz provides a theoretical data-rate of 7 Gbit/s. The trade-off is limited range and penetration. The main reason for this awesome data-rate is a 9 GHz bandwidth, from 66 GHz to 57 GHz. I ...
2
votes
1answer
325 views

A 40MHz oscillator in usb wifi adapter

I disassembled a usb wifi adapter. I was surprised to see a 40MHz oscillator, when wifi works at 2.4GHz. How the output of the oscillator is scaled to the required frequency?
5
votes
1answer
2k views

Why do bluetooth headsets get interference (choppy sound quality) outdoors?

This is more of a general physics question to help me understand how to choose sports headsets in the future, however it is too specific to a certain use case (bluetooth headset) to belong in the ...
0
votes
2answers
100 views

How can I make a GPS traceable microchip? [closed]

I am looking for making a chip or a microchip, which can be traced with the help of the satellites. Means it is merely a chip and when I tune my satellite to a particular frequency I would get to know ...
9
votes
1answer
4k views

What is the difference between Bluetooth Low Energy and Bluetooth BR/EDR in Park mode?

It is known that Bluetooth Low Energy transmits data only during short time intervals called Connection Events. Connection events occur regullary with predefined period. The rest of the time Bluetooth ...
2
votes
0answers
52 views

Effect of bad weather on P2P Communication or Broadcasting?

I stop receiving TV signals whenever their is cloud cover outside. On the other hand I have never had any such problems with my internet connection or GPS system. I cannot understand why and how often ...
2
votes
3answers
200 views

Why not only GSM (3G/4G/..)? Why do we need Bluetooth, Wifi,etc…?

It is quite frustrating to have multiple adapter for connecting to desktop. For example, if I want to connect my phone to desktop I need Bluetooth/wifi; why can't I just just use the Mobile's main ...
3
votes
0answers
131 views

How is modulated the Primary Synchronization Signal in LTE?

PSS is based on 62 values from a Zadoff-Chu sequence. Three different sequences can be used by an LTE Cell, to represent the Physical Cell ID within the Cell ID group. The formula is the following, $...
1
vote
1answer
66 views

Will the water in a gold fish bowl signficantly abosorb Bluetooth or WiFi if transciever is at bottom of bowl?

Using WiFi or bluetooth frequencies 5.8GHz and 2.4-2.485GHz respectively, I want to place a hermetically sealed circuit at the bottom of a gold fish bowl, and want to know if the water will ...
3
votes
0answers
43 views

What is PSS waveform formula?

I want to know how is exactly modulated a LTE subcarrier. Since I'm working on Synchronization Signals (P-SS, S-SS) the subcarriers I'm talking about are centered around DC. I have coded the ...