# Questions tagged [communication]

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

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### Does DSB-SC signals retain original shape of the message signal $x(t)$ when $x(t) <0$?

The conventional DSB-FC AM signal is given by: $s(t)=[A+x(t)]\cos \omega _C t$ In conventional DSB-FC AM we take care of the fact that $|x(t) | <A$. So that the modulated signal is not ...
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### Transmission of information in terms of information theory and protocol

I am a student studying wireless communications. First of all, I learned that In AWGN channel, i.e., y=x+n with n~N(0,sigma^2), the amount of information that can be transferred (i.e., capacity) ...
135 views

### How is the power of a SSB-SC signal half that of DSB-SC signal?

Intuitively I get it that my SSB power has to be half of DSB power but mathematically I am unable to get this. Say working for tone modulation. $$m(t)=mA\cos(w_mt)$$ where m is modulation index. ...
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### XBEE S3 PRO loses comms beyond 800 meters with a 7dbi Antenna

My XBEE S3 PRO loses some packets when transmitting 800 meters away from the XBEE Pair. Even though we used a 7 dbi car antenna with sma jack. we used a jack converter from sma to rp sma (if that ...
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### What is the meaning of reciprocal communication range in the context of wireless communication?

Does it mean the carrier sense range is equals to the communication range, as this paper mentions the system has no hidden terminals due to reciprocal range ?
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### What are the equations/values for Rayleigh Fading, path loss and log-normal shadowing?

I am to use the following equation as part of a model for a wireless communications network: I would like to know the specific parts of the eqautions: "k" - is this the Boltzmann constant? "v" - I ...
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### Peak-to-Average Power Ratio in OFDMA Communication

I am looking for a formula to calculate the Average Power of a square wave used in APSK Modulation. In my textbook, the example above is given with no formula so I am a loss how the value for ...
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### Multiple input to single output converter and vice versa

First question so please forgive any mistakes. I'm trying to design a system by which multiple LEDs are controlled by multiple switches, but without using as many wires as there are switch/LED pairs. ...
45 views

### SPI terminology confusion for project

I am working with the FET335xS-II OBC developed by Forlinx for a school project. On the data sheet, There is no indication of pins pertaining to MOSI and MISO but instead "data 0" and "data 1". I am a ...
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### Does disconnecting the Tx+ and Tx- wires in the ethernet cable make it Unidirectional for Packet (TCP) sniffing

The DCSW-1005(10/100Base-T) Ethernet switch/TAP can be used as a network TAP (as well as Ethernet switch), in which a copy of outgoing and incoming packets associated with Port 1 (Target port) are ...
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### Why is there no reponse from ModbusRTU slave using converter?

There are two devices: Eaton EM20/M (~like Northern Design Cube 400) Volison ADM-5850G Connected them like: Trying to get data from EM20/M which supports ...
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### SIM800L cannot init

I'm working with SIM800L for remote-sensing communication via GPRS. The problem is, everytime the module is running initialization function (SIM800.begin(), different for every SIM800L library), it ...
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### Finding required BW with Bessel table

The FM signal (see image 1) is applied to a 50 Ohms antenna, and I am seeking the required bandwith with the Bessel table (image 2). From the FM signal, I deduced that the information frequency is ...
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### Noise power at receive antenna with finite transmit SNR?

I have seen a few examples of link budgets, and they all assume that the total noise at the Rx is just going to be -174 dBm + 10 log BW. However, this seems to me to assume that the transmit signal is ...
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### How does GSM Module store incoming SMS in its “SM” or “ME” memory?

I am using AI Thinker A7 GSM/GPRS/GPS Module demo v7.1.(The Rx, TX, GND pins of this module are connected to tx, rx, gnd pins of the prolific Rs232-TTL converter and a virtual com port is open in ...
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### Communication Theory - Determine efficiency of this protocol

My solution: I have no idea if what I did is correct. I'm getting a bit confused differentiating between 500 frames/minute and the 4.8Gb/s, they both seem like transmission rates to me. I'm assuming ...
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### Communication Theory - Basic Transmission Errors

I have a question regarding some basic transmission error: My confusion is with the solution to combat errors (transmit each frame 3 times). I would have though that the probability of receiving a ...
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### Write collision for multiple reads - PIC24 I2C

I am trying to poll a CAP188 sensor so I'm sending it read commands in a while loop, but the first read works and then on the second read when I send the slave address it detects a write collision. ...
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### 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 ...
101 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 ...
156 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 ...