Questions tagged [communication]

Exchange of information between devices. Communication can be wired or wireless.

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Frequency Deviation is given by del (f) = KfAm (Kf= frequency modulation sensitivity and Am= Amplitude of Message signal)

Then why has it been divided by 2pi, as shown in the image. Really confused. Please help.
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45 views

Radiofrequency exposure from portable (vehicle-mounted) satellite uplink antennas

I came across these broadcasting vans recently in London. The antenna that's deployed I think is a Vislink Advent uplink antenna, similar to this model, designed to transmit to satellites for ...
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1answer
39 views

Increasing satellite communication capacity - bullet point list help [closed]

What are the major drivers for increasing satellite communication capacity? Bandwidth (Nyquist theorem) Frequency reuse via multiple spot beams in an antenna coverage area Higher SNR gives better BER,...
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2answers
74 views

Lack of 'determinism' in Ethernet bus

While reading this website, I found out tha there is lack of 'determinism' in the Ethernet network bus as compared to some other buses like 1553. What I understand is that Ethernet is a single master ...
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2answers
79 views

What is used as a rotary join in Lidar system? [closed]

I want to transfer data between a rotary platform mounting an antenna and a PC, so I can scan for a signal at 360 degrees. I could use a slip ring but there is a loss in signal. I want to transmit ...
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2answers
74 views

Is there a method to get the carrier from the recieved QPSK signal?

If we have given a signal and we know that is a modulated QPSK signal, can we recover the carrier if we know the carrier frequency fc. Edit: A clarification, I do not have to do it in hardware, a ...
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33 views

what's up with u-law companding when u is 0

https://www.tutorialspoint.com/principles_of_communication/principles_of_communication_modulation_techniques.htm It says that I can get the compressed output of a signal using this: it also says ...
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1answer
32 views

What is the difference between residual phase noise and absolute phase noise?

Studying the characteristics of an oscillator with a phase noise analyzer, but I don't quite understand the difference between absolute and residual noise. Any help would be greatly appreciated
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18 views

Foster - Seeley FM Demodulator Explanation

Consider this Foster Seeley Demodulator If I have correctly understood, its basic working principle is the fact that at the secondary coils (L2) of the Balun there will be two signals equal and ...
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2answers
68 views

Can we band pass filter QPSK signal?

Consider we have QPSK signal with carrier frequency 10kHz. Generally, we demodulate or use matched filter on the the QPSK signal and recover the transmitted bit or the symbols. If the QPSk signal is ...
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40 views

How can line code polarity inversion happen?

One of the disadvantages of some line codes like NRZ-L or RZ is that if a sudden change in polarity occurs, then all received bits will be erroneous (flipped). How can such a sudden change in ...
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2answers
101 views

Measure voltage on 48 batteries at once using microcontroller

I am looking to design a microcontroller that can measure the voltages on 48 batteries. Some of the batteries will have floating voltages as the device is wired in a parallel string of 8 columns, with ...
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30 views

MCP2561/2562 CANbus voltage?

The datasheet says the MCP2561/MCP2562 is suitable for 12V and 24V systems except that everywhere I look in the datasheet it says VDD needs to be between 4.5 to 5V. How can CANH be greater than VDD or ...
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2answers
103 views

Extremely low data rate transmission over long distance for attinys

For a lighting project I need to be able to trigger 20 units every couple of seconds independently which are daisy chained with 1-2 m space between each of them like so: Control station ====== Unit 1 ...
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40 views

Are magnetically tunable surface acoustic wave devices commercially produced?

I have been reading up on studies of magnetically tunable surface acoustic wave devices, in general they note the relative velocity change or in some cases a frequency shift if it is part of an ...
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1answer
92 views

What chips can be used to design an Anti-Counterfeit /Authentication circuit? [closed]

I am an intern within the R&D branch of a company that designs tools that must operate with low noise at extremely high external temperatures (upwards of 175C). My boss asked that I look into ...
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Xbee Router in API mode not sending frames from UART input?

My current system is setup as follows: MCU ------ Xbee A(Router) ------ Xbee B(Coordinator) Xbee A is a router in API mode, Xbee B is a coordinator in API mode. MCU is MSP430, Xbee modules are ZB ...
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42 views

Can I use a Ku band satellite dish for Wi-Fi?

Satellite TV works at 18-24Ghz and WiFi at 2.4Ghz, will a T.V dish antenna work for WiFi? Diameter of the dish is about 60-90cm
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57 views

Digital transmission of composite video [closed]

As the tittle suggest, I was thinking about making a wireless composite video transmission between a small camera (such as those sold for flying fpv) and a receiver. The two main specs it must have is ...
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1answer
67 views

Communication between device for 5 meters and low speeds

I need to make a communication between only two devices with a distance of 5 meters, which are connected by a cable of 4x2.5mm² (see in the image), being 1 wire for GND and wire for 12v, that would ...
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3answers
60 views

Does data rate increase with channel frequency?

It is commonly said that a higher channel frequency implies a higher data rate. For example, in https://www.howtogeek.com/222249/whats-the-difference-between-2.4-ghz-and-5-ghz-wi-fi-and-which-should-...
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1answer
62 views

How to calculate the 3dB point?

I understand this until the final two lines. How does he get from 27.8766 to 1149.8hz and 7224.7rad/s?
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Average and maximal number of time slots in adaptive tree walk protocol

I was wondering if it is possible to know the maximal and average number of time slots that will pass until and including the time slot in which there will be a successful broadcast, knowing that two ...
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1answer
67 views

Bluetooth vs BT Beacon [closed]

While trying to understand how BT devices work I came across another related term "BT Beacon". Is it same as BT communication or if a device is termed as BT beacon then it would have some specific ...
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1answer
45 views

I/O expanders- CAN & I2C

Currently in my system we use 16 I/O expanders with I2C interface. I want to change it to CAN interface. Which is the best possible way without compromising the cost? I tried searching for 16I/O ...
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30 views

Implications of using a 2C-#18 twisted shield pair nec type cmr cable for RS-485

The cable will be passing modbus and another equal cable will be used for loadshare. The total cable distance will be about 100ft. Its catalog number E2032S. I notice other threads related to CAT5, ...
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23 views

Bluetooth Mesh Module

So I would like to design a device that allows me to send instructions to different devices (each containing a HC-06 Module). I would like to ask if it would be ideal to use a Bluetooth Mesh? This is ...
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3k views

How fail-safe is \n\r as stop bytes?

In my UART communication I need to know the start byte and the stop byte of the message sent. The start byte is easy but the stop byte, not so much. I have implemented two stop bytes at the end of my ...
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20 views

calculating the probability of a successful broadcast in p-csma protocol

am quite unsure with the following question. would appreciate your help with it: in a 3 stationed p-csma network, where \$p=0.3\$, we know that in \$t_0\$ the network is restarted, the channel is ...
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1answer
67 views

RS422/RS485 data input series resistor

I am using an RS422/RS485 driver to send Arduino 5V logic data over longer distances. I use the SN75174 driver for this purpose. In order to avoid ringing, I am not sure if I have to connect a series ...
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1answer
82 views

Weird character from UART. STM32L100RC

I'm having problems communicating with UART on my STM32L100RC discovery board. I get character such as xþ when I'm sending the letter 'F'. I'm using Hercule to receive data. Hercule's configuration is ...
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58 views

Finding the overhead and distance of an unknown code based on message making algorithm

for an information word M with m bits that is coded as following: M is coded into a word A using an unknown code that allows detection of not more than one error. the code word is the word obtained ...
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45 views

Why always in communication protocols R/W configuration,Reading is configured by “1” and writing by “0”? [closed]

when a microcontroller communicates with another one via one of the communication protocols there is a configuration bit in a control register to choose whether to send(write) or receive(read) this ...
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2answers
94 views

RF communication vs Bluetooth [closed]

I'm starting a new project in my Electrical Engineering degree at my university and I need help. Overall, my project is about a mini robot that collects data and sends it (via wireless communication) ...
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44 views

What effect do R5,R6,R7,R8 have on the following DSBSC Modulator?

I know that the first 741 essentially adds m(t) and c(t).The gain should be 1 so why do we have 3.9kohms resistance ? What use is it ? The second 741 circuit is a band pass filter . I think there is a ...
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80 views

TCA9548A (I2C multiplexer) works for a few minutes and then hangs

I'm having trouble getting the TCA9548APWR to communicate for longer than a few minutes. I'm only able to get it to "reset" by resoldering it. I have used both an Arduino Mega and a Beaglebone Black ...
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29 views

Antenna formed from the RF module shielding wall and cover

Can anyone provide details how an antenna can be designed from RF module shielding wall or cover? More specifically if any company is making this kind of antenna product for general communication or ...
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1answer
44 views

How is the power calculated for Si(t) in the picture?

The formula I've seen is to multiply the signal by its complex conjugate, then integrate across the time period interval, and then divide by the period. But when I do that I don't get A^2/2
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63 views

Demodulation of a 38 kHz IR PWM signal

I want to learn how to demodulate a 38 kHz IR PWM signal.(Such as that transmitted by a TV Remote Control) I know it can be demodulated easily using a TSOP1738 IR receiver. I realize that the ...
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21 views

NB-IoT/CAT-M1: Llimitation to the actively connected devices

For the new Cellular IoT technologies NB-IoT and CAT-M1, is there a limitation to the number of modems that can be connected to the base station at one time? I tried searching for this but I couldn't ...
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1answer
122 views

How does Nyquist bit rate formula relate Bandwidth, Signal Rate, and Bit Rate?

I know what each of Bandwidth, Signal rate, and Bit rate mean. But I am having trouble in their mathematical relationship with each other. I will use the notation of the textbook I am reading from (...
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51 views

a tricky question regarding CDMA with 4 stations

i have encountered this tricky questions that left me really confused, would really appreciate your insight regarding it: given a cellular system with four stations that utilizes CDMA. given the ...
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32 views

Data communication in power harvesting project

I want to design a wearable gadget for elderly to detect falling. This gadget should work by energy harvesting. Now I want to find the best effitient way of power consumtion to send data to a station ...
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3answers
90 views

Choosing best bus and protocol for ~128 clients over the wire

I am up to design system with ~128 MCUs communicating to one MCU master. Communication will be bidirectional. Data will be mostly sensor reads, but I plan to use the bus also as communication method ...
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1answer
42 views

What are the factors that affect delay/latency between base stations?

I am modelling a 5G network, with the uplink and downlink being decoupled and treated as separate networks. I am exploring the integration of fog computing and how latency varies between different ...
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42 views

Intercom device, door-opener and door-bell

I got a Bticino intercom system (non-wireless). I did some restoration in my hallway and disconnected the device. Unfortunately I do not remember how it was wired before I set it up afterwards. Now we ...
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42 views

Wifi coaxial cable type unknown

Quick question, I was unable to identify the coaxial cable type used in wifi devices(routers ,tablets,etc.) , very thin grey cable approximately 1mm in outer diameter, I need to know the type so I can ...
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1answer
91 views

How do I stop signal looping with I/O port in this communication system

I am still a student. When I am designing communication system I am facing this problem: As shown in the figure I need to communicate with Master and Slave. But Master and Slave have single I/O port ...
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67 views

Generating a specific sequence of signals in Verilog with timing requirements

I am a beginner in Verilog, and as a part of a project, I have to send a sequence of signals to a chip in order to program one of its parameters. This Verilog code will be synthesized on an FPGA, and ...
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2answers
64 views

What does the phase discriminator portion of the Costas Receiver do mathematically?

What does the phase discriminator portion of the Costas Receiver do mathematically? The output of the I-channel is \$ \frac{1}{2}A_C \cos \phi m(t) \$. Which means for small deviation of phase \$ \...