Questions tagged [communication]

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

112 questions with no upvoted or accepted answers
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202 views

Home made passive tablet pen

I have an old wacom tablet at home, its really big and I'd like to use it but I've lost the pen for it. It uses pens with passive LC circuitry. The board creats an EM-field (I can see it on my ...
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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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1answer
413 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?
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1k views

ASDA-A2 RS-485 Communication Configuration

First of all, I know that my question is very specific for those who have hands on experience with the ASDA-A2 Servo Drive from Delta-Electronics. But I hope that someone will guide me through the ...
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43 views

How to pick a Balun and transformer for this power line measurement circuit

I was reading this paper here about measuring power line impedance using a network analyzer. It has a little circuit that they used but of course they're not nice enough to include a BOM :) How ...
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0answers
1k views

What is bit-true implementation

What is bit-true implementation (with an example if possible)? I was reading a paper and it was stated "a bit-true implementation of the algorithm on a FPGA was performed." So what exactly is bit-...
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559 views

Which serial protocol or encoding scheme does this scoreboard use?

I am trying to decode a signal stream coming from a Nevco scoreboard controller: Packets like this are sent every ~2.7 ms. I suspect it is some sort of UART signal because it is on the RX line of a ...
2
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1answer
8k views

LIN-communication between two STM32F4 with a standard LIN-transceiver (Hello World)

I have the following circuit connecting two stm32F4 via the SN65HVDA195-Q1 LIN-transciever. simulate this circuit – ...
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0answers
3k views

why is shadow fading also called slow fading and large-scale fading?

I've encountered several similar claims regarding shadow fading on several books, and have some difficulty understanding them. (1) Shadow fading is called slow fading because the duration of the fade ...
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1answer
2k views

Esp8266 nodemcu v3 connection to usb fingerprint scanner

My project is about making an ioT biometric attendance management using Esp8266 nodemcu and a Morpho usb biometric scanner. So my question is whether is it possible to connect a usb fingerprint ...
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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
38 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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22 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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42 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
68 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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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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71 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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52 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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31 views

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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211 views

Honeywell I2C RH Sensor SDA line experiencing fluctuation between Vdd and Vdd/2

I had a problem when implementing I2C communication between NXP Kinetis K50 micro-controller and Honeywell Humidlcon I2C RH sensor. The RH sensor doesn't acknowledge when receiving the default address ...
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32 views

ENC28J60 rejects unicast packets - unicast filter is on, MAC is set, and addresses match

I'm programming an ENC28J60 driver at the moment, and have encountered something odd when attempting to receive packets. More specifically, unicast packets. According to the datasheet, when the ...
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1answer
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 ...
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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 ...
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2answers
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 ...
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1answer
368 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 ...
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1answer
189 views

What kind of communication protocol is this?

I'm trying to reverse engineer the communication between two modules, a master and a slave, but I couldn't figure out the used protocol. All of the signs use 5V. The blue sign's frequency is 400 kHz. ...
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2answers
250 views

Noise resilient, hot-pluggable communication bus over long cables?

I'm working on a setup, where we need communication between a master device and several slave microcontrollers distributed out in different boxes connected by "long" cat5e cables (3-10 meters) The ...
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1answer
164 views

How to interpret this CAN bus data and find an equation?

I am trying to reverse engineer the data sent from an old CAN bus data logger. It sends a single ID which is selectable from a dip switch. The only bit of data I am struggling with is the RPM I plan ...
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2answers
196 views

S/N Formula with probability

Hello I am looking for the S/N formula that incorporates the probability of catching the signal, and setting an arbitrary treshold level above which we detect the signal. I can't figure out the ...
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0answers
226 views

Circuit to drive a telegraph sounder?

I acquired an old telegraph sounder, marked Western Electric 140 Ohms, and have a Morse code key. What voltage should I drive the sounder with to hear the proper Morse code click sounds when keyed? ...
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2answers
1k views

For a wireless channel, what is the difference between Ergodic capacity and Outage capacity?

What do the terms Ergodic and Outage mean? And how do they relate to Shannon capacity?
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139 views

How to network hundreds of sensors over a serial connection?

So I'm looking for a way to connect hundreds (300-400) sensors (like an accelerometer) together over a serial connection to a micro-controller. The sensors would transmit about 500kbps each. I've ...
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0answers
37 views

Sources of online broadband RF energy data stream?

I am interested in finding recordings of broadband FM radio emissions, ideally in the marine VHF frequencies (156.0 and 162.025), in order to understand carrier artifacts and distortions that could ...
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0answers
66 views

Compressed single-sideband modulation?

I've had an idea for a new form of SSB modulation, using half-angle formulas as a basis for compressing the sideband of a SSB voice transmission. However, this idea seems so simple that I feel it must ...
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71 views

Computing the received signal

My question may seem a little bit easy but I'm new to these concepts and was hoping if you could help me clarify them by answering my questions. The received signal at the detector writes: $$ y = h x ...
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0answers
493 views

What is Virtual Array Antenna?

What is virtual array antenna (VAA)? I have searched it everywhere but i was unable to find direct answer to this question. I know this concept was built from phased array antenna. Please explain ...
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0answers
350 views

How to reduce SPI bit errors between a Bus Pirate and a BIOS chip?

I need to eliminate bit errors when reading a BIOS chip using a Bus Pirate v3.6. The BIOS chip is still soldered onto the motherboard. I'm using a Bus Pirate probe set to connect the Bus Pirate to a ...
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125 views

USB signal analysis

I have a device that I want to control it has window software that runs it, and a complex interface. I just need a pair of commands, also I know very little about usb device hacking, and signal ...
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52 views

Compression and communication power consumption trade-offs

Let's say I'd like to save battery power consumption when sending data to remote devices connected wirelessly, i.e., sensor networks. One of the ideas may be compressing the data to reduce the number ...
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0answers
185 views

Sub-1 GHz Narrow Band vs Wide Band

As per the TI document I came across which compares narrow band sub-1 usage vs wide band sub-1 usage mentions a concept called coding gain and its disadvantages. Because of my lack of understanding ...
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0answers
85 views

Definition of “hot” resistor when calculating RMS thermal voltage?

I am calculating the RMS thermal noise voltage of a "hot" resistor of a tutorial sheet for uni. I have used the standard Johnson–Nyquist formulas, but the answer sheet does not include the entire ...
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0answers
794 views

PCIe card powered but not recognized on custom interface

I have a black magic declink mini recorder card that I am trying to recognize on a small form factor linux machine (debian 3.2.46-1 x86_64). I have made a custom interface board with what I think are ...
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0answers
570 views

MIMO with directional antennas

In the context of a competition, I need to set up a wireless link between a base station and a mobile target. The mobile target: -> will always be within the same 180 degree cone from the base ...
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0answers
482 views

Arduino to Serial Cable Encoding Error

I am trying to send data between an Arduino Uno and a Mac. The Arduino Uno is running this simple sketch to print data to serial: ...
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0answers
1k views

Communicate through a VPN link using Arduino Uart WiFi Module

Following describes the configuration of the system and other details. The problem is mentioned after that. If the initial description is too much or not needed, please skip it. I have a VPN (between ...
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0answers
647 views

Connecting 2 Arduinos with Bluetooth

I have been looking on Google for a project that involves 2 Arduinos communicating with Bluetooth. The only examples I can find are with an Arduino to an Android phone. Does anyone have links to let ...
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0answers
898 views

PIC32 read feedback from UART

I'm using a PIC32MX795F512H to set up a Roving RN-131 wifi module using UART. I can communicate with the device but I want some feedback whether my commands are processed or not. I basically need to ...
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37 views

Need help in computing the evolution of symbol error rate for uncoded OOK scheme over fading channels

I am trying to reproduce the results exhibited in Fig. 1. in the reference, i.e., "Error performance of coded FSO links in turbulent atmosphere modeled by gamma-gamma distributions" linked to (https://...
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42 views

Writing Flash Memory Serially

I am looking into writing data onto some Flash memory serially, the requirement is to replace the old parallel programmer with a serial based programmer example Cheetah SPI Host Adapter. The Flash ...
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17 views

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.