# Questions tagged [communication]

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

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### Why are Erlang B and Erlang C formulas different?

Erlang B determines the probability that a call is blocked and is defined as: $$Pr[blocking]= {{A^C \over C!} \over {\sum_{k = 0}^{C} {A^k \over k!}}}$$ while Erlang C determines the probability ...
35 views

### utilize a single channel to transmit data generated from 16 users (using mux)

I have found this question in a book and find it confusing. The question is, For a communication system, it is required to utilize a single channel to transmit the data generated from 16 users. ...
17 views

### dsb_sc of sin wave

Can we take the dsb_sc(Double side band suppressed carrier)of a sinusoidal signal I know that it exists for cosine but for sine I can't find anything on the internet
849 views

### Analog beamforming vs digital beamforming

I am reading some research articles on wireless communication where they talk about beamforming techniques and their differences in Multiple antenna Tx-Rx systems (MIMO). It says analog beamforming ...
1k views

### Is this communication I²C?

I need to decode communication between two devices, but I have no information about these devices. All I know is that four wires are needed (GND, VCC and two wires of communication). I suspect that it ...
44 views

### Power of random signal in AM

I'm trying to wrap my head around this problem : I must admit I'm pretty much blocked from the start, at a). I don't understand how I could derive the power of $s_{AM}$ given the frequency of the ...
94 views

### Communication between a Computer and Microcomputers

I am currently working on a project that require me to communicate between several Raspberry Pi's and a computer. I'll display data that sent by Raspberry Pi on that computer. Since I am using ...
109 views

### PLC as gateway with TCP/IP communication stack?

I'm having issues designing an architecture for communication in a vehicle. Currently a PC is connected through a switch to a series of ECUS, each one with a TCP2CAN converter. The PC has to be ...
157 views

### Methods for confirming on both sides that a signal was received in one direction

Say there are two devices (A & B) that talk to each other (full duplex). For the sake of this example, let's say the medium is RF (wireless). If device A sends a message to device B, what ...
57 views

### Which material is considered non linear communication channel?

Communication channels as far I have seen(Air and conductors) are modeled as Linear systems. Was wondering if there are mediums/materials that make the channel nonlinear? For example, if channel is ...
101 views

### PC to Rasberry Pi Serial Communication

Im trying to communicate to my pc using my raspberry pi using a software called Docklight. I'm using a serial cable (that i ripped apart) and my breadboard as shown below. Now, you can also see I ...
136 views

### Fast, cheap, wireless data transmission with Raspberry Pi [closed]

I need some advice on a project. I want to wirelessly transmit packets of data from a Raspberry Pi to several microcontrollers (Arduino or other). The frequency must be at least 15 packets/s per ...
5k views

### Is it possible to send multiple data bits on a single wire at once?

Is there an existing protocol or modulation method where multiple data bits are sent over a single wire at once or maybe an additional ground line (like serial communication)? I know there are ...
580 views

### Why do we use a DB9 connector for serial com?

We only use 4 wires (pwr, common, and two data), so why does rs232 use such a big connector?
174 views

### Fiber-optic transceiver ICs for applications other than fiber-optic Ethernet? [closed]

When we talk about fiber-optic transmission, we almost always talk about copper to fiber-optic Ethernet conversion using fiber-optic transceivers. But since fiber-optic communication is just ...
99 views

### Cheap Low Power Signal Transmission To Smartphone

For my university project I'm making a certain sensor which has to (one-way) communicate with a smartphone. The sensor needs to be as cheap/simple as possible (aiming at +- €0,50 in total) and only ...
42 views

### Method to find Correlation for a random variable and thereby power spectral density of random signal

I'm trying really hard to understand the segment of text from a standard communication book ( Modern digital and analog communications by B P Lathi). We are trying to find the power spectral density ...
288 views

### How to make communication between microcontrollers

I want to make a project where it is necessary to communicate between several microcontrollers in the fastest way possible. For that matter I have 10 micro-controllers whose names will be 1 ... 10: ...
412 views

### SPI with differential signaling

Standard SPI uses single-ended signals. Is it possible that a communication uses SPI protocol but the signals are physically LVDS?
748 views

### RS485 to RS232 conversion?

I need to connect a sensor that uses a RS485 transmission to RS232 or something I can read through the com ports on my data logger. I can't use usb ports or virtual com ports due to the program I am ...
97 views

### Connect three HC-05 Masters to three HC-05 slaves

I have 3 Bluetooth modules HC-05 connected to my laptop using an USB-TTL interface and 3 microcontrollers each one has its own HC-05 slave. These devices shall send values to my laptop (each slave ...
90 views

### RS-485 + iCE40 for better CAN-FD

This is an idea I have been toying with for a while and wanted to get an opinion. When I first heard about CAN-FD I thought it was going to be the answer to this problem. However most mid range ...
171 views

### UART Data Transfer Across Modular Boards

I am trying to create a modular system that uses UART to broadcast the same data to each microcontroller that gets added to the system. It could have 3 or it could have 10 modules added to the system. ...
189 views

### SPI read error with MCP2515

In an attempt to interface a motor controller, battery management system and maximum power point tracking device on a CAN bus, I used the MCP2515 and TJA1050 CAN breakout board. All these devices send ...
57 views

### Meaning of Evolution in LTE (Long-Term Evolution)

The term Evolution/Evolved (E) is everywhere in communications, and simply put i don't understand why. The answer I am looking for is one that will help me know what meaning i should associate with ...
124 views

### How to configure my xbee s2c modules for communicating with arduinos + sensors?

I have two xbee module (fixed on a development board), these boards does not have a individual access pins to access xbee pins (photo included), but rather a RS232 port. As for what I have searched, ...
331 views

### What is mean by Differential Daisy Chain UART?

What is mean by differential daisy chain UART? And what is the difference between UART and differential daisy chain UART? While reading datasheet I come across this concept if anybody knows then I ...
537 views

### Is a 'timeout' of 0.2 ms for UART communication realistic?

In most examples (from Arduino/STM32/whatever) I see timeouts of 10 to 100 ms for different kind of communication. However, I am wondering how much 'overhead' there is. Assuming I want to send 8 ...
62 views

### Nrf24l01 module works on breadboard but not on pcb

After using a breadboarded nrf24l01 for more than a year, I decided to shrink it and have it on a pcb using the wiring diagram exactly used in the breadboard. I am attaching the pictures of the first ...
48 views

I have a very limited number of outputs available (4 to be exact) on my existing PLC and need to share 5-7 bits of information to another PLC without having the expense off add-on communication cards. ...
77 views

### How does the data rate of a CAN bus affect the value of the capacitor used in a split termination scheme?

I'm helping to redesign the CAN bus of an electric car, and we're interested in achieving higher data rates of up to 8 Mbit/s. We have a transceiver selected, a CMC to reduce inductively coupled ...
58 views

### Do I need to connect the battery to send data to an ESP32 chip?

This may be a basic question, but I'm really new to electrical engineering. I got an ESP32 chip with no micro-USB port. I got with the device a 3-Wire cable one side and USB other side. I have to ...
107 views

### power and signal inside shielded CAT5 cable

I'll use a shielded CAT5 cable for RS485 line. The simplified bus structure is drawn in the picture . I have 130 slaves and their isolated part of RS485 IC is supplied from the supply placed at master....
116 views

### Setting up a 485 network

I have a problem where my 485 transceiver just get damaged at field, when it's at laboratory everything runs fine, now reading about it I saw that 485 requires a 120Ohm impedance on both ends and bias ...
133 views

### What USB-2 cabling hardware do I need to connect two Windows 10 computers together? [closed]

I want to run a .NET app in each of the two computers, so that they send and receive data through USB-2. What kind of cable adapter will do this? BACKGROUND: I need to build a GUI on Windows that ...
46 views

### Tail biting Convolution Encoder

I understand how encoder and decoder works but what are theses values ??
471 views

### Raspberry Pi Zero connection to sensor (with I²C or SPI bus interface) over a large distance

SUMMARY: Here is what works: Raspberry Pi (I²C) <-> 1 m cable <-> sensor (I²C) Here is what I'm trying to do (doesn't work, hence question): Raspberry Pi (I²C) <-> 30 m cable <-> ...
286 views

### ESP32 AND CP2102 Serial data reading issue

I have a PCB on which i am taking a 5v - 1A DC power supply , and again providing 3.3v to ESP32 through AMS-1117 3.3v. Basically things are not working on when i solder the esp32 on my pcb but things ...
358 views

### CRC hardware implementation

What is the difference between these two implementations as the feedback is in first implementation the last reg only but the second implementation last reg xored with the input bit, so, what is the ...
81 views

### verilog assign memory in a memory

I want to assign a memory 64x6 in a memory 64x6 by saying that all the 64 rows in memory_2 will be equal to all the 64 rows in memory_1, how to make that in verilog ?? knowing that it is very easy in ...
61 views

### Send data from MCU to Embedded Linux CoM

I'm using an ATSAME70Q21 MCU to record 32 channels of analogue data (via SPI ADCs) and 32 channels of digital data (via GPIO). My embedded device has an iMX6-based CoM (Toradex Apalis), which runs ...
256 views

### understanding of UART , if two devices share a common ground. How do they get to the same voltage level for a save data transmission?

My question is related to the common ground in a UART communication. So far, what I understand how communication in general works is: Distinguishing the voltage between two cables (one is a GND and ...
55 views

### Connecting mixed-speed multiple serial devices to two microcontrollers

I'm trying to figure out the best way to integrate all devices flawlessly on the 8051 based microcontrollers. If each device was the same low speed, then I could multiplex each and every one of them ...
94 views

### How to wire RJ12 to db9f modular adaptor?

I have a RJ-12 to DB9f modular adapter. There are 6 wires that come out of the adaptor (White, Black, Red, Green, Yellow Blue) - these, as I gather from pin out diagrams, correspond to the 6 jacks of ...
113 views

### Which cable for 230.4 Kbps RS-232

I have to communicate between a sensor module and micro-controller board. The sensor module uses UART at 230400 bps. I have used a MAX3227 on sensor module as well as micro-controller board. So, the ...
72 views

### What do I need to do to connect an ADC IC to a Adam 6066??Is it even possible to read the inputs from the ADC chip?

I am working on a input array that uses a ADC (MCP3208 or something similar) to read in several analog inputs and convert them to Digital signals that go into an ADAM 6066 Module. What would I need to ...
56 views

### suggestions for a ~20cm 2 way wireless communication between arduino like devices

I am trying to build a system where, when and only when someone is within close proximity, about 20 cm or so, two arduino like devices can communicate wirelessly. I want to be able to communicate ...
3k views

### Why is “wavelength” used as a unit for the length of an antenna?

We often refer to antenna size relative to wavelength. For example: a 1/2 wave dipole is approximately half a wavelength long. Wavelength is the distance a radio wave travels during one cycle. (...