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Exercise on PPM modulation bit rate

A digital communication system uses N=15 identical routes. The modulation used is 2-PPM. Calculate the value of $$ \varepsilon_b/N_0 $$ on the exit from the first route so that a final error ...
user44128's user avatar
5 votes
3 answers
816 views

Telecom cables for power transmission

Summary: Can I use abandoned telecom wire bundles as a 3-phase neutral? Our campus currently has underground AC cables supplying 2 legs of 3 phase wye power to a remote (50 ft away) building. There ...
madarp's user avatar
  • 63
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0 answers
10 views

Are LTE-M or NB IoT Sim modules (eg from simcom) carriers restricted?

I am currently planning to build a board which will have to use LTE-M or NB-IoT technology due to their low consumption and because I do not need large data bandwidth. The targeted region is Africa. I ...
HGO's user avatar
  • 21
-2 votes
1 answer
61 views

Was there ever a protocol to send profanity censorship tones out-of-band over television, so that viewers could turn them off? If not, why not? [closed]

These days, in the Western world, closed captioning is delivered out-of-band, so the captions are not actually part of the video itself, allowing viewers to turn them off if they are not desired (...
Felix An's user avatar
7 votes
6 answers
5k views

Ethernet port as a signal generator

I was wondering if it's possible to turn a PC into a signal generator through the ethernet port (or at least an amplitude-modulated sine generator). I specifically care about the ethernet port since ...
KKZiomek's user avatar
  • 141
-1 votes
1 answer
70 views

Data rate for an ASK modulation [closed]

A telephone line with a bandwidth of 3 kHz and an SNR of 6 dB. I am asked to calculate the maximum bitrate on this line and the error probability, knowing that ASK modulation is used. For ASK ...
Mouh Kramo's user avatar
1 vote
1 answer
29 views

Why Phase1 GSM is mentioned to be a 3GPP release?

In some references such as Wikipedia (although wiki is not a reliable reference), GSM phase 1 is mentioned one of 3GPP releases while 3GPP itself is founded in 1998/1999 while GSM Phase 1 is ...
VSB's user avatar
  • 412
1 vote
2 answers
109 views

What component could be

I have a VDSL telephony socket with some electronics in it. I reverse engineered the PCB, but there is one component I cannot identify at all. Look like a 0.25W TH resistor, light-blue body and a ...
Zoltán Gógucz's user avatar
18 votes
3 answers
3k views

How does a UK analogue telephone detect that the caller has hung up (disconnected)? [closed]

Scenario This is a question regarding the design of UK analogue telecommunications equipment and the consequent design impact that is necessary for a router duplicating those signals. It is asked so ...
user2834566's user avatar
0 votes
0 answers
20 views

Noise in mm-wave initial access frameworks

I have a doubt about Initial Access (IA) procedures in mm-wave system. In most papers I have read (see e.g. Initial Access in 5G mm-Wave Cellular Networks), most of the alignment procedures assume ...
Apprentice's user avatar
2 votes
2 answers
418 views

Why do shift registers (LFSR) use the initial state "all 1"?

In all books about information coding theory, scientists describe shift registers of various configurations, but they always use the initial state "all 1" in any configuration and any bit ...
Daniel's user avatar
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0 votes
2 answers
172 views

How to manage multiple devices connected to the same antenna?

I'm planning to connect an SDR in 'parallel' to a modem used to transmit and receive a radio signal on 2.4/5.8 GHz. The SDR that I want to use is the HackRF one, which can receive up to -5 dBm in ...
TheRealBen's user avatar
0 votes
0 answers
82 views

Intersymbol interference on PAM Trasmitter

I would like to simulate on Matlab a PAM signal which, travelling on a time-dispersive communication channel, contains intersymbol interference (ISI). I have 'built' the transmitter by generating: 8-...
KaleM's user avatar
  • 419
0 votes
0 answers
86 views

Devices to measure RSSI and/or AGC

I need a way to measure the strength/power of a signal coming from an antenna, 2.4 or 5.8 GHz frequency. Is there any off-the-shelf device that can measure such property? Ideally I would want the ...
TheRealBen's user avatar
0 votes
1 answer
37 views

Is it possible to to use same frequency band and same frequency blocks for two adjacent/near telecom circles

As shown in the Screen-Shot, TRAI (Telecom Regulatory authority of India) in the pre-auction recommendation manual to DoT(Department of telecommunication) mentions 770 MHz of the spectrum ( 35 MHz for ...
Samdare's user avatar
0 votes
1 answer
227 views

Why do we modulate a signal before the transmission? [duplicate]

I have a fundamental question. Why do we modulate a signal before the transmission? What is the obstacle for transmitting a signal in its typical form?
mohammad rezza's user avatar
1 vote
3 answers
292 views

Is it possible for satellite communication to have less latency than cable and optic fiber?

I would expect satellite internet to have large latency. Apart from Starlink this holds for most of the rest. It seems you could argue that information travels a larger distance with respect to fiber ...
Mah Neh's user avatar
  • 23
2 votes
2 answers
114 views

Calculate the mean of signal \$ e^{-j2\pi t^2} \$

I'm a trying to calculate the mean value of the signal \$ e^{-j2\pi t^2} \$ Here is my attempt: $$ <x\left(t\right)>\triangleq\lim_{T \to \infty}{\frac{1}{2T}\int_{-T}^{T}x\left(t\right)dt}=\...
WienerKhinchin1Fan's user avatar
0 votes
1 answer
44 views

How do modulations depend on transmission media? [closed]

or how is transmission media affected by modulation? Is there any relationship?
alfonso's user avatar
  • 457
1 vote
2 answers
423 views

How does multiplying the modulated signal "AGAIN" by the carrier frequency transfer the spectrum back to its original position?

I have some trouble understanding the demodulation of a signal. SI understand how we multiply the message signal by the carrier signal then chuck it through a channel, but on the receiver side I don't ...
MALLU's user avatar
  • 69
3 votes
2 answers
104 views

How is fiber coupling achieved in communication?

Optical communication with (single-mode) fibers is widespread. Pretty much the complete internet backbone is based on it. However, I am wondering a bit how the light is coupled into the fibers. ...
cakelover's user avatar
  • 453
0 votes
0 answers
47 views

Difference of Milenage Version 1 and Version 2

I've heard in the telecom industry about Milenage Version 1 algorithm and Milenage Version 2 algorithm. I want to know what are their differences? The version 1 and version 2 have the same length for ...
VSB's user avatar
  • 412
0 votes
2 answers
190 views

Transmission Line model [closed]

Can some one explain me why exactly classical circuit theory fails to account for the wave nature of EM fields and how the transmission line model accounts for it better
Jirhs Kumar 's user avatar
0 votes
2 answers
787 views

Why are microwaves unidirectional and radio waves omnidirectional?

I understand that any wave can be given direction using a setup like a phased array. As I read about the properties of EM waves, I find that microwaves are unidirectional in nature. What is it about ...
k.h's user avatar
  • 103
2 votes
2 answers
398 views

How can the Earth be used as a return path?

I was reading an academic document and I came across this statement: Telegraphy, 1747 (a singe-wire line with the Earth as a return conductor – the first transmission line) I can't imagine how that ...
MALLU's user avatar
  • 69
1 vote
1 answer
254 views

Hamming code error correction multiple bits

If we send a message from a sender and the noisy channel produces 2 bits with error can we detect both bits using hamming code or is it just for 1 bit?
Jun Seo-He's user avatar
6 votes
2 answers
1k views

Why is the telecom input power supply range 36 to 72 V (polarity ignored)?

Why is the telecom power supply voltage level specifieded with a wide range: 36 to 72 V? Is it because the rectified AC voltage would have variations as per AC line variations? We could easily get a ...
Dynamic_equilibrium's user avatar
1 vote
1 answer
59 views

Questions about understanding networks (Telecommunications eng)

So I read about Network topology, about typs of communications like ptp, ptmp, mptmp and about Addressing methods (multicasting, broadcasting), etc... I'm very confused. What is the difference between ...
user310644's user avatar
2 votes
1 answer
348 views

How to convert data signal line coding from RZ to NRZ?

I have a user data stream at 10 kbps and line coded as uni-polar, 0-5 Volts, RZ (return to zero). What methods are there to convert this signal to an NRZ (non return to zero) format? The only way I ...
user3425949's user avatar
1 vote
0 answers
54 views

How should I understand this interpretation?

Studying spatial diversity in telecommunication engineering (Fundamentals of Wireless Communication, D. Tse and P. Viswannath), I read this paragraph. $${\text {In}}\,{\|}{\textbf h}{\|}^{2}{\text {...
P Dude's user avatar
  • 11
0 votes
0 answers
58 views

Can I reconstruct the channel impulse response from OFDM least square channel estimation?

I'm working on a successive interference cancellation (SIC) project for an OFDM system. I used pilots and least square channel estimation to estimate the channel frequency response (CFR.) It works ...
Han Miao's user avatar
0 votes
0 answers
46 views

How to do a comparative analysis of electrical characteristics of two 134kHz RFID circuits?

In the figure below there are two antenna circuits, both are circuits used in RFID at 134kHz, which are external to the TMS3705 IC. Circuit number 1 is an old circuit, circuit number 2 is the circuit ...
Daniel's user avatar
  • 917
0 votes
0 answers
38 views

Find Bps given a star graph

Today I wrote finals for the semester in the subject "Introduction to Telecommunications".1 question was like this: Suppose we have a star graph with 64 dots in it.That would mean we are ...
Jun Seo-He's user avatar
0 votes
1 answer
145 views

How to switch off the CATV signal on a splitter port

I'm trying to create some automation of switching off the CATV signal on a splitter port. Using a regular 5V Arduino relay module I've tried to interrupt the wire from the center of the coaxial cable ...
Mne's user avatar
  • 1
-3 votes
2 answers
226 views

5G and aircraft? [closed]

I just read the statement of a company, "We are frustrated by the FAA’s inability to do what nearly 40 countries have done, which is to safely deploy 5G technology without disrupting aviation ...
riccs_0x's user avatar
  • 530
1 vote
0 answers
158 views

Optical Receivers and Amplifiers

I have been doing some past papers for a university module I am studying. I am not from an electrical engineering background so don’t really know how to attempt the question attached. I would really ...
Jamie's user avatar
  • 11
14 votes
4 answers
5k views

What is the purpose of a carrier signal in communication technology?

What is the carrier signal for when we actually do not care about this but only about the other signal (the useful signal?) Why isn't only the useful signal used instead of mixing it with the carrier?...
Ben's user avatar
  • 625
3 votes
0 answers
118 views

Identify this telephony or data connector?

Recently I had the opportunity to visit a telecom/data room that was being decommissioned. A lot of the remaining equipment seemed to be from around year 2000 or so, as best as I could tell. While ...
StayOnTarget's user avatar
  • 1,236
0 votes
0 answers
75 views

LTE Bandwidth at band edge

If my LTE uplink channel is right on the band 20 edge for example 861.9MHz or 24449 EARFCN and my LTE BW is 10MHz does that mean the final signal would be outside of B20 or 856.9-866.9 ? Or is the ...
Engo's user avatar
  • 11
2 votes
1 answer
221 views

How are simultaneous transmissions decoded at the receiver?

I am finding it hard to understand how does a receiver differentiate between the interference and the signal intended for the corresponding receiver. For example in a case where two user pairs are ...
ZZ1's user avatar
  • 33
1 vote
3 answers
381 views

Manchester and NRZ coding schemes

How does NRZ recover the clock? For example, Manchester coding is a self-time scheme, but we still need to have DLL or PLL for the recovery, it can be done without those CDR circuits? and back to NRZ, ...
Hammam's user avatar
  • 11
16 votes
3 answers
1k views

What is this circuit diagram found on an FM transmitter?

This is the circuit diagram on the transmitter at a local FM radio station I clean at (I'm a janitor,) but I'm also studying electrical engineering. I'm puzzled by the circuit diagram on the ...
Jessica Ham's user avatar
1 vote
0 answers
28 views

How to find priori information in Cramer Rao Lower Bound when the pdf of the parameter is unkown

In order to compute a Bayesian Cramer Rao Lower bound, we need to find the prior information of a random parameter "theta" which is a complex scalar parameter. The pdf of "theta" ...
saulgoodman's user avatar
0 votes
1 answer
62 views

What is 'mis-registration' and 'mis-collimation' of television signals?

I was reading about early televisions and television cameras, and I came across these terms with no explanation.... They appear on Google on a few pages, but again I cannot find a definition....
Kurt Hikes's user avatar
0 votes
1 answer
164 views

NOAA satellite RF superhet receiver - local oscillator frequency precision

I am currently designing a RF receiver for the APT protocol in order to collect NOAA weather images. This has been widely done on the internet, but I'd like to do it from scratch and not use any SDR. ...
Clément Chaine's user avatar
0 votes
2 answers
2k views

Dwell time in wireless communication

In wireless communication dwell time is defined as the amount of time a device uses a particular channel. If we take the case of a ...
Franc's user avatar
  • 93
1 vote
2 answers
5k views

What does GSM 900/1800 mean?

I was looking at old Nokia 3310 phones, which have GSM 900/1800. I did some research online from a government website, along with some Google searches, to understand what GSM 900/1800 means. I got a ...
questioner's user avatar
8 votes
5 answers
4k views

Was the last mile copper wire not the limitation in dial-up internet service?

My local internet service providers can provide ADSL (asymmetric digital subscriber line) service at various speeds, for example, 50 M bits per second. This service is in Canada. Is this typically ...
H2ONaCl's user avatar
  • 371
4 votes
2 answers
543 views

Modeling bidirectional communication across a coax?

I was reading about the history of cable internet and I'm interested in a simple model of full-duplex communications across a single coaxial cable. My first attempt is simply a transmission line with ...
Mark's user avatar
  • 231
1 vote
1 answer
669 views

Amplitude Modulation Equation (sine or cosine)

I got an exam tomorrow and I'm still confused with something. I'm sure most people are familiar with the general equation of Amplitude Modulation. AM(t) = (Ac+m(t))cos ωc t I found that there is ...
Syahrul's user avatar
  • 13