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

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29 views

RS485 half duplex communication issue

I have a London MR400s taximeter and I wanted to communicate with it so I have connected it with my PC using RS485 half duplex cable. I am using termite terminal for polling and receiving the data. ...
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3answers
52 views

using C libraries inside verilog

I'm implementing a radio in Verilog. the time taken for bit reversal while computing the FFT is more. it is almost equal to a symbol time (OFDM system). Can I use a FFT library in C, which can be ...
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2answers
46 views

Industry standard ways of connecting boards / modules?

There are literally thousands of different types of connectors when I'm searching on a distributor such as element14, and I'm not sure what are the "standard" ways of connecting boards together. ...
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1answer
47 views

Connection problem with RS485 system on PC with RS232 port

I am developing a system in which I have to integrate hardware. I am from computer background, so I don't have much knowledge about hardware systems. The issue is I have to integrate with London ...
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2answers
138 views

Communication between micro controllers - I2C, SPI, UART?

Basically I have two microcontrollers that I need to communicate with each other. Both controllers send and receive data. Basic idea that I have: I2C, SPI - What I think we can NOT use these ...
2
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1answer
58 views

Finding the Power developed by the Nominal Frequency in FM

Question The sinusoidal signal \$f(t) = \cos(2 \pi f_m t)\$ is applied to the input of an FM system. The corresponding modulation signal output for \$f_m = 1kHz\$, is $$Q(t)=100 \cos(2 ...
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0answers
58 views

1 Mbps satellite channel with a 270 ms delay

Consider 500 byte frames sends on a satellite channel with a 270 ms delay on send an receive by 1 Mbps rate. by ignore the length of ACK message and using Slide Window technique, how many bits need ...
1
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0answers
58 views

Finding the bandwith of FM by using Bessel functions with 1% rule

Question A 100-MHz carrier is frequency modulated by a 10-kHz sinusoid so that the peak frequency deviation is 30 Hz. Using Bessel functions with 1% rule, i.e. 40 dB down from the unmodulated ...
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2answers
72 views

How wireless communication works?

When an AC signal is transmitted through a conductor, direction of flow of electrons is continuously alternated. In wireless communication signal is transmitted through air, in this case which ...
5
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1answer
358 views

Transceivers in the field of FPGAs: When and why will we use them?

I am recently getting myself into the field of FPGA design and development, and lately I've found myself hearing a lot about transceivers. I tried searching the net for some answers about these ...
0
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1answer
30 views

Prove a theorem about an upper bound for entropy of a random vector

There is a theorem that: if Z is any zero-mean, complex random vector with covariance \$E[ZZ^H]=R_z\$, then \$H(Z)\leq \log|{\pi eR_z}|\$, with equality holding if and only if Z has a circularly ...
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4answers
112 views

How does a CPU choose a path? [closed]

This is the most baffling question of all other concepts. I ask my teacher "How does the computer choose a path?" "They program it" "How do they program it?" "..." I have a basic understanding ...
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1answer
50 views

Link Capacity and the Shannon-Hartley Theorem

I'm reading Computer Networks: A Systems Approach by Peterson and Davies. One of the examples demonstrates the relationship between link capacity and the Shannon-Hartley Theorem. We can find the ...
0
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0answers
36 views

Form of the received signal in a MIMO communication

I am reading an article which is related to MIMO communication networks. Consider that there are \$U\$ users, each of them have \$J_{u}, u=1,...U\$, different layers. We want to calculate the received ...
1
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2answers
60 views

Address and communicate with multiple devices in a matrix

I have a large matrix of devices, "nodes", that I would like to address and communicate with - assume > 50 nodes. Each of the nodes have a controller that receives data from a central microcontroller ...
0
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1answer
35 views

How to find the fundamental frequency and present harmonics from a graph?

I'm having a very hard time understanding frequency and harmonics and now that I'm working on problems, I am completely perplexed. The problem reads as follows - Assume that string of bits ...
0
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1answer
91 views

Finding the power output when one single sideband at m=0.4 is transmitted together with the carrier component which is reduced by 26dB

Question An AM transmitter has an output of 24kW when modulated to a depth of 100%. Determine the power output from first principles when one single sideband at m=0.4 is transmitted together ...
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1answer
99 views

Daisy Chaining ADC Sensors

I'm creating a grid of 200+ pressure sensors and need a clean way to get their values back to the master controller without a mess of wires. To me it seems like daisy chaining all the sensors ...
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2answers
161 views

Double Side-band Amplitude for Radio Transmission & Single Side-band Reduce Carrier for Point-to-point Transmission

What are the reasons which lead to the use of double side-band amplitude for radio transmission, and single side-band reduce carrier working for point to point transmission? Thank you for your help.
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2answers
65 views

communication 101 [closed]

I have a couple of really basic questions. (1) When a device(Device 1) communicates to another device(Device 2), do the devices have to operate in the SAME frequency for the data transmission to take ...
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0answers
48 views

Which communication protocol to use [closed]

Consider two devices having a basic radio transceiver (and use the same frequency) and a base station which uses a different frequency radio. The data from base station should be broadcasted to both ...
0
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2answers
64 views

Why is the data rate a function of the length of the transmission line?

The length of a transmission line is limiting the highest possible data rate on that line. Why are faster signals more likely to become corrupted on long transmission lines than on shorter ones, with ...
1
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0answers
78 views

Why is “throughput” called “bandwidth”?

But back in school, I had learned that the "bandwidth" of a communication channel is the frequency of the highest-frequency signal minus that of the lowest-frequency signal that it can carry. Yet in ...
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1answer
125 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?
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0answers
59 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
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1answer
92 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 .
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1answer
94 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 ...
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2answers
83 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
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1answer
52 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
50 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
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2answers
93 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
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1answer
84 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
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1answer
97 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
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4answers
112 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 ...
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1answer
98 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
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0answers
13 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 ...
2
votes
3answers
123 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
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1answer
61 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
83 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
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1answer
55 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
102 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
266 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
416 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
77 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
47 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 ...
3
votes
1answer
167 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
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2answers
89 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
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0answers
108 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
289 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
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1answer
48 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 ...