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

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0answers
32 views

Data Communication [on hold]

Hello gusy can any help me to calculate this thanks. A baseband analogue signal has a bandwidth of 42 kHz, and is used to modulate the frequency of a carrier signal at a frequency of 327 MHz. ...
0
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1answer
89 views

Why AM is preferred over FM in long distance communication?

In almost all long distance communication AM is preferred over FM. Do type of modulation has anything to do with this or it is just depending on transmitting frequency?
-4
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0answers
23 views

Best wireless mesh technology with great indoor range for sensors project? [on hold]

I'm working on a project that will have many different sensors in complex of few building, I would like to cover whole place with sensors. Idea is to document it and give out our solution in fully ...
1
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0answers
46 views

Ethernet communication [closed]

I want to make a simple program which achieves Ethernet communication. Specially I will try to connect this ENC28J60 Ethernet LAN Network Module and make a simple real time monitoring application ...
-7
votes
1answer
77 views

Signal jammer circuit design [closed]

This is a circut for a jammer for the 450Mhz , but my calculation says it's for 277Mhz. If I want to prepare for a gsm 900 , what changes would I have to make .
0
votes
1answer
65 views

Two arduino unit communication

OK plain and simple I'm not sure to use IR or RF. This is short distance up to maybe 10 ft. I have an Arduino Uno that I have all set up here. I press a button and it carries out its code. This is ...
0
votes
1answer
49 views

Amplitude modulation of unit step signal

What will be the amplitude modulated signal, if the input is an unit step signal? You can take any carrier signal (though I would recommend sine wave) and take any carrier frequency because that is ...
1
vote
1answer
34 views

Beagleboard USB Packet sniffer

I had picked up a beagleboard a few weeks ago and had then looked into the USB sniffer project that had been created a while back. (https://gitorious.org/beagleboard-usbsniffer/) I understand that ...
2
votes
2answers
45 views

Trying to Understand Spurious Sideband Interference (and some causality problems…)

Suppose I have a radio and I intend to transmit a 0.1 µs pulse on a 100 MHz carrier. Fourier theory tells me that this signal will produce some sideband interference resembling a Sinc function. ...
0
votes
2answers
63 views

Pictures of different adapters, trying to understand how they work (PLC to PC communication)

I purchased the blue adapter in the picture as a USB/RS232 converter. It takes in the RJ12 cable from my PLC, and converts it to a USB input. Now when I try to use an RJ12-DB9 Female and then connect ...
1
vote
1answer
65 views

How does USB 3.0 negotiate power states?

I noticed, in another question, a comment regarding USB power states. I know that USB 2.0 negotiated power by tying the D+ and D- lines to specific voltages but I can't seem to find any information ...
0
votes
1answer
61 views

Can I transmit data over RJ12 to a PC from a PLC?

I have a Click PLC which has two RJ12 ports. I have successfully programmed it using C# and nModBus as a slave, but now I want to test the PLC as a master and the PC as a slave and noticed my laptop ...
0
votes
4answers
65 views

Slowest transmission speed supported by TOSLINK TX and RX?

I'm writing an Arduino communication library that uses differential Manchester coding (see: http://forum.arduino.cc/index.php?topic=257985.0). I'm wondering how to communicate between two Arduinos ...
1
vote
1answer
47 views

Shannon versus Nyquist bit rate calculations

I am confused with the shannon channel capacity formula Versus nyquist bit rate. nyquist formula contains signal levels while Shannon formula doen't, how to refer to signal Levels in shannon's ...
0
votes
0answers
11 views

How do Coherence Time and Coherence Bandwidth influence the decision on the diversity scheme?

I came across a statement in a lecture slide which states: Coherence Bandwidth and Coherence Time govern our decisions about the diversity scheme that we would choose The lecture is in the field ...
0
votes
0answers
4 views

Serial communication between pc and arduino via RS232 using c++ [migrated]

I am trying to communicate with my arduino duemilanove via an RS232 cord. I simply want to be able to send a byte (or char) to my arduino from a desktop application. The Arduino is plugging into USB ...
2
votes
3answers
112 views

What happens if SINR is < 1?

What happens if the SINR of a signal is less than 1 in a (wireless) network? Is that practical at all to have a SINR < 1? Using the Shannon capacity formula, it seems that we must be able to have ...
0
votes
1answer
46 views

Check me on this modulation question?

I need to check my answers for parts (a) and (c); a) I got q(t) = p(t)cos(5pit) c) i got y(t) as a rectangle with amplitude 1 from -pi to pi. So, y(t) = 1/8 f(t) Am I correct for both parts;
3
votes
1answer
61 views

AVR - ATmega16 - Timer config

Trying to figure out the timer setup in Atmel Studio 6 for an ATmega16 microcontroller. And I just don't get it. I am trying to create a TickCount similar to GetTickCount() Retrieves the number of ...
1
vote
1answer
54 views

Bandwidth of CW modulation (morse code)? [duplicate]

How can I relate the bandwidth required by a morse code signal over RF to: the length of a dash, and the length of a dot the time between dots and dashes the speed of keying? Are all applicable to ...
2
votes
0answers
86 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 ...
2
votes
2answers
94 views

Signal rate, data rate and bandwidth in digital signals

I'm trying to understand the concept of signal rate and the relation between signal (baud) rate and bandwidth of digital signals from a book about data communication. First, the book distinguishes ...
3
votes
2answers
405 views

Bandwidth for a single tone

If I am using a channel only for morse code (CW), with one frequency and interruptions for dots and dashes, is the necessary bandwidth of the channel twice the audio frequency of the tone used for CW? ...
3
votes
1answer
68 views

Bluetooth low energy communication

I was wondering if it is possible to communicate between 2 BLE devices when one is placed inside the car and another placed outside the car. Can BLE communicate in such a scenario? For example, I ...
0
votes
2answers
35 views

the response of wireless channel to an input

I am reading the wireless of David Tse. In the 2nd chapter of this book there is a discussion about the response of the channel due to an input. It has said that since the channel is linear its output ...
2
votes
1answer
92 views

What's the maximum CAN bus frame (message) rate at 125 kbit/s?

My CAN bus is running at 125 kbit/s and is using extended frame format exclusively. I would like to know what's the maximum rate of CAN frame I can send out. Suppose the data length is always ...
1
vote
2answers
83 views

Explain Rayleigh Fading in plain English

For a couple of days I am trying to understand the Rayleigh Fading model, but I am failing to. I look at various articles and tutorials online, everything goes fine up to a points, but then a lot of ...
0
votes
0answers
73 views

Read and write FPGA registers via USB or Ethernet

I'm working on an FPGA project on an Atlys Spartan 6 board. I'm programming it in VHDL. I have two 32 bit registers, one for output, the other for input. I need to be able to, respectively, read and ...
2
votes
2answers
135 views

GPRS data call using GSM/GPRS modem (Siemens TC35 and/or MC35)

I'm developing a data aquisition module, that amongst other things, it have to comunicate through GSM/GPRS module, since it will be a mobile application. I can connect to the module and send sms's ...
1
vote
1answer
45 views

What happen if 0 and 1 are transmitted simultaneously with BPSK?

I'm just curious that what happen if 0 and 1 are transmitted simultaneously from different source nodes to an equidistant destination node with BPSK? Assuming perfect signal shaping, synchronization ...
0
votes
1answer
50 views

frequency allocation for telecommunication companies

For a high bit rate in data communication we need a high bandwidth. Suppose there are hundreds of carriers in a particular region and they are all allocated microwave frequencies. Minimum spacing ...
1
vote
1answer
65 views

Quantization levels and SNR

Im' trying to build a big picture of telecommunication and i'm stuck in a topic, related to digital communication. But the problem is that i can't go too deep into the topic because it is imensely ...
1
vote
3answers
146 views

How do you achieve an efficiency of more than 1 bit per Hertz?

I believe this is also known as spectral efficiency - apparently it's possible for us to transmit more than one bit per Hertz. But to my layman mind I imagine a Hertz being only capable of ...
1
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1answer
36 views

Real Time Data Capture System

I would like to build a system which could capture an analogue waveform data in real time. For the basic data acquisition system I can use an ADC to digitise an analogue waveform and store this in a ...
2
votes
1answer
55 views

Wireless telecom system (cellular with Erlang and spectral efficiency)

We have a spectrum of 20MHz that we will use on a wireless cellular system, which requires 50kHz per channel. The system is using cluster size K = 4 and the radius of every cell is R = 1 km. a) ...
0
votes
0answers
25 views

Calculating Eb/No for a desired Pe for a matched filter

can someone verify that I am doing this right. I have been given the question: In most applications, communication systems are designed to have a Pe of 3E-5 or less. Find the minimum Eb/No required ...
1
vote
1answer
64 views

Calculating the output power from an Amplifier

This is not based on any particular hardware. I am trying to understand the theory behind it by doing tutorial questions from my uni, I have completed the question but don't understand the approach ...
1
vote
1answer
130 views

What is the 'best' way of communicating with small microcontrollers/devices?

var best = "simple & cheap"; I have a server in my apartment that I have an XBEE hooked up to. I use it to communicate with another XBEE plugged into an Arduino. I am trying to hook up many ...
1
vote
0answers
53 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 ...
1
vote
1answer
66 views

Xbee configuration with X-CTU on linux

I'm trying to configure an XBee with the X-CTU tool using Wine. I followed the steps given in this tutorial. I plug the USB in and check the kernel logs to see on which serial devices it has been ...
0
votes
2answers
51 views

How does Signal-Noise-Ratio related to receiver power

If I have the instaneous Signal-Noise-Ratio (of the receiver), but no other information, and I am interested in the instaneous \$\mathbf{Power_{received}}\$, is there any relationship between these ...
1
vote
0answers
57 views

How to calculate Input backoff per carrier of a satellite

I was trying to calculate the sizing of SSPA in my satcom network where input backoff per carrier is required to calculate Power flux density. My current network configuration in C band is Total ...
0
votes
1answer
52 views

Cell in Cellular communication

When they talk about the "cell" in cellular communication, they often refer to the shape of hexagon. If I am correct, this is probably the coverage area of the transmission base tower. SHouldn't be ...
0
votes
3answers
88 views

Long distance communication

I am looking for a cheap single wired solution to transfer data of some sensors connected to a uC over a distance of 1 KM from a control room on UART. The data is of 16 bytes, no high speed ...
0
votes
2answers
142 views

Why is propagation delay of ethernet cables unaffected by cable length?

I did some searching on how propagation delay in ethernet cables is affected by the cable length. The answer seems to be that the delay is negligible until the cable length reaches a kind of threshold ...
4
votes
2answers
82 views

660 Mbits per second photo-diode amplifier on 3.3V rail

I've got a 10mW laser diode that can transmit at 660 Mbits per second, I've got the laser driver circuit that can do this, I've got a photodiode from Hamamatsu that looks good for this speed (-3 dB ~1 ...
0
votes
1answer
116 views

I get back wrong chars from bluetooth module (uart)

I would like to communicate between my atmega8 controller and PC via an HC-06 bluetooth module. I should get back the same char that I send but I get some wrong characters. The bluetooth module uses ...
0
votes
1answer
131 views

Max Distance for 5V serial communications

I have an application where two different microcontrollers need to communicate. I was thinking that for simplicity, just use 5V instead of converting to RS232 levels. What in good practice would the ...
0
votes
1answer
51 views

Definition of link gain for an optical system

Is the link gain the gain of the whole system or just over the diode? And why does the threshold current of a diode laser have no impact on link gain whereas increases in slope efficiency have a major ...
0
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1answer
73 views

Designing a simple energy-efficient communication protocol?

What is the required background knowledge in order to be able to understand and work on the design of a communication protocol which has to be robust, simple and capable of coping with short contact ...