Related to all communication systems that use a given digital sequence as an interface between the source and the channel input.

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0answers
37 views

VIsible Light COmmunication using Arduino for masters thesis [on hold]

I am currently doing my Masters in electrical engineering. As part of my Master's thesis I want to conduct some research/project in Visible Light Communication using arduino. I have a time frame of ...
3
votes
4answers
741 views

How much binary data is transmitted across a physical wire in one clock cycle?

How much voltage change, what I'm calling binary data, can be transmitted over a wire at one time in one clock cycle? I understand, I think, binary data is what we call it and the wire doesn't really ...
-1
votes
2answers
33 views

Which modulation is suitable for OFDM sub-channels?

As we all know, OFDM consists lots of sub-channels and different sub-channels can be modulated in different way independently. So among OOK, ASK, BPSK, MPSK, QAM, FSK, MSK, which methods are suitable ...
2
votes
1answer
37 views

How to design a transistor current switch for synchronization circuit?

The following diagram is a practical diagram for derivation of the clock signal from the received waveform itself (Synchronization) in baseband PAM systems. I'm looking for a typical circuit for ...
1
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3answers
65 views

Lightweight point to point communication protocols

I'm working on designing a point to point communications link for a cubesat. I just want to confirm some of my understanding. In my opinion it is only necessary to have physical layer and data link ...
1
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0answers
53 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 ...
2
votes
3answers
56 views

UART Receiver Sampling Rate

I am trying to create a UART receiver in Verilog for my FPGA. I was following this guide http://www.fpga4fun.com/SerialInterface4.html According to it the standard practice for asynchronous ...
1
vote
3answers
49 views

How to add (all zero state) to the states of linear feedback shift register (LFSR)

I need to add the state of all zeros to the states of an linear feedback shift register. How can I do this?
0
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0answers
38 views

Duplicate Error Detection Problem - Logic

Duplicate Error Detection Problem - Logic Questions with 9 bit word The sender sends an 9-bit word { x1, x2, … , x8 , px} with even parity in duplicate. The receiver receives the following two words ...
0
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2answers
64 views

Would it be possible to design a SoC have to two antenna? [closed]

If you use an actual SoC such as the Qualcomm Snapdragon Processor for mobile communications would it be possible to have two cores both sharing a common IO (Cellular/WiFi/GPS/Bluetooth) integrated ...
1
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0answers
24 views

Electric Vehicle Temperature Monitoring

I'm looking to implement a system to monitor the cell temperatures of about 80 cells in a 240-cell battery pack for an electric vehicle (yes, at least 80 cells must be monitored). I'm looking for a ...
9
votes
4answers
1k views

Why the integral is zero

I wonder why under assumption that \$\omega \gg \frac{1}{T}\$ then \$\int_{0}^{T} \sin(\omega t)dt \approx 0\$? Since the integral should be like \$\frac{\cos(\omega t)}{w}\$ from \$0\$ to \$T\$ and ...
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votes
1answer
42 views

HDB3 Waveform: Determining the bit sequence

I was asked to determine the bit sequence of a given HDB3 waveform. I understand that if there are three consecutive 0's then the fourth in that sequence must be a violation pulse. In this example ...
0
votes
0answers
26 views

SQNR for different step sizes in quantising the same signal

Assume a random signal uniformly distributed between +5V to -5V. Here, for positive and negative halves i get two SNRs. For positive half 0 to 5v ; number of bits =7 and SNR = 43.6dB. while for ...
0
votes
1answer
72 views

Data encoding for GFSK wireless

We are designing a RF link (2GFSK) using the CC1125, to replace and older system. The older system uses NRZI data encoding with bit stuffing. Bit stuffing is used to remove the present of stop flag ...
0
votes
0answers
29 views

What is the difference between polar and bipolar line codings?

In a book I found that in polar line coding the interval is (-A/2---+A/2) and in bipolar it is (-A---+A). Is it correct or polar and bipolar are just same?
1
vote
1answer
43 views

Quick digital receiver for Manchester encoded data?

I want to implement a digital Manchester encoded data receiver. The application is not dissimilar to the KeeLoq system. That is, there is no time for long link training - I want the receiver to ...
2
votes
1answer
66 views

Bidirectional Digital Communication over Audio Signal?

I am trying to figure out a way to achieve low speed digital communication over an audio line. I have two devices that are connected with a two wire audio cable. Audio and Ground. From my research, I ...
4
votes
5answers
658 views

What happens when two digital circuits are connected and one is powered but not the other?

Assume the following, generic, configuration in which two digital circuits are interconnected but have independent power supplies (e.g. two redundant microcontrollers). simulate this circuit ...
0
votes
1answer
108 views

Digital Level Shifter with Op-Amp

I'm trying to design a simple level shifter to read the digital output of a sensor into a beaglebone GPIO. The sensor output is either 0V or the 24V supply voltage, although a different supply voltage ...
0
votes
2answers
92 views

TMP04 Temperature Sensor with Arduino Not going HIGH

I have a TMP04 temperature sensor (3 pin package). It outputs a square wave at approximately 35Hz and the duty cycle can be converted into a temperature reading (see datasheet). It has an operating ...
1
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0answers
35 views

AC Noise in UTP cable for Wiegand26

I have situation where i need to capture wiegand26 signal. I use it on single twisted pair. But i get a lot of AC noise in UTP cable Cat 6. Shield is not connected anywhere. The ...
1
vote
1answer
34 views

Finding the DFT size in relation to an OFDM encoded signal

I am completely lost here. How do I go about determining the size of the DFT matrix used in conjunction with an OFDM encoded signal? I have researched this a lot but cannot find a solid answer? Is it ...
1
vote
1answer
84 views

is multipath the real cause of small-scale fading?

Since I was a student I've been told that small-scale fading is due to multipath propagation. With multipath you get constructive and destructive interference making the signal received power fade. ...
1
vote
2answers
84 views

applying for loop [closed]

I want to apply for loop. Below is my code. I have applied the for loop which is wrong. Here Length(t) is sample numbers. Here I want to create 'for' loop for a sample number 5 in particular. so how ...
1
vote
0answers
32 views

Storing pulses, then releasing them on trigger

I have a BeagleBoneBlack microcontroller that can generate pulses and clock for SPI. These pulses have rise times of a few tens of nanoseconds, which is nice. Unforunately, the BeagleBone is ...
1
vote
2answers
169 views

How to model Phase noise?

I want to model phase noise. Code below shows how I am adding phase noise in the signal. However, i am not getting correct output. That means, the signal sprectrum shoud be spreading in the frequency ...
3
votes
2answers
222 views

How Channelization code is shared in HSDPA?

I am on my way to understand the HSDPA/HSUPA technologies. I have just started and came upon the topic of channelization code. I learned how these codes are generated - Hadamard code technique - and ...
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votes
2answers
75 views
-1
votes
2answers
96 views

Which of the following is most limiting factor for data transmission rate? [closed]

Which of the following is most limiting factor for data transmission rate? Attenuation distortion Phase delay Signal distortion Bandwidth I think its phase delay, but I am not sure. Can someone ...
0
votes
1answer
70 views

Estimate the bandwidth required to transmit 1Mbits/s of data using a modulation scheme which comprises 32 different frequencies and 2 amplitude levels

Estimate the bandwidth required to transmit 1Mbits/s of data using a modulation scheme which comprises 32 different frequencies and 2 amplitude levels Yes, this is a homework question that ive been ...
0
votes
3answers
89 views

PIC24f Get Clock Signal for external Device?

I have an external memory device with pin configuration: Data Input Data Output Connection System CLock DC 24V Ground Here is the link I need to design a code to communicate with this device. I ...
0
votes
1answer
90 views

Logic Level Shifter

I am trying to connect two devices on a PCB. One operates with 3.3V digital high and the other works with 5V digital high. I actually grouped the input and output pins (There is no bidirectional ...
3
votes
5answers
815 views

Transmission of a digital signal over a medium

A digital signal is said to have a infinite bandwidth. If a transmission medium cannot have infinite bandwidth then how can a digital signal be transmitted over such mediums? Please correct me if I ...
1
vote
1answer
72 views

what is the function of pre-emphasizer and dee-emphasizer in Stereophonic FM Receiver?

what is the purpose of theses two block ? I know that pre-emphasizer will boost the high frequencies before transmission and dee-emphasizer will reducing them by a corresponding amount in the ...
0
votes
3answers
304 views

How to reduce rise/fall time while amplifying square pulses with op amp?

I'm trying to amplify a low signal with square pulses at 20 mV using op amps. According to simulation, rise and fall time of pulses increase too much after amplification, approximately 60 us. The ...
1
vote
0answers
107 views

How to amplify a signal containing square pulses at milivolts to a couple volts

I was on it for a time. I'm planning to generate a signal containing square pulses from a smart phone's audio output. As I can get any shape of audio signal from smartphone's audio output, I want to ...
1
vote
2answers
128 views

555 as a Digital Coupler

I want to read MIDI data with an arduino (specifically an ATtiny85) for use in a synthesizer. The only method I'm aware of involves using an optocoupler such as the 6N138 found on this Instructable. ...
0
votes
0answers
35 views

duobinary coding : how to find if there an Error in a given sequence?

why we can't have even number of zero between opposite polarity ? is the same things applies for even number of ones between opposite polarity
2
votes
1answer
112 views

FSK combined with either ASK or PSK?

Why is it that we are able to combine Amplitude and Phase modulation (Resulting in QAM) but are not able to do so with frequency? Why not combine all three degrees of freedom (Amplitude, Frequency, ...
0
votes
3answers
91 views

Transmit an internet connection over wireless

My target is to transmit an internet connection (8 Mbit/s) over long range wireless RF (7.7 km) with LOS (Line Of Sight). I live in a country where there is no rules for RF transmission, so i can use ...
3
votes
1answer
99 views

Multiple SPI Busses in Ribbon Cable

I have a multiple SPI busses running through a ribbon cable which is 15cm long. What is the best CS, SCK, MOSI, MISO orientation to avoid the cross talk between each wire and is it enough to use ...
1
vote
1answer
97 views

How do you design a circuit to implement the Bipolar Line coding Technique?

Bipolar NRZ http://www.tutorialspoint.com/data_communication_computer_network/images/bipolar.jpg In this technique alternate 1's will have alternate polarities and 0's will be zero itself.
0
votes
3answers
65 views

Spreading of a pulse in time domain

I have a small doubt. Suppose I transmit just 2 square pulse with frequency of 100 MHz over a wireless channel, will it spread in the time domain when received by a wireless receiver. In other words, ...
0
votes
1answer
132 views

Weak pull down for SPI

I am using Arduino(does not matter) and 8 x 12 bit-ADCs to read some values. I created a prototype which consists of a Shift Register(SR) and all outputs of SR are connected to individual ADC's ...
1
vote
0answers
205 views

Porting Costas Loop from Matlab to FPGA

I have designed a Costas Loop for carrier synchronization in MATLAB, here is my code: ...
0
votes
1answer
74 views

Is it safer to use multiple RS-485 point to point connections compared to a daisy chain?

When wiring multiple RS485 slaves to a master equipped with a RS232/RS422/RS485 interface*: is it safer to wire multiple point to point connections from the hub with their own termination resistor, ...
13
votes
4answers
2k views

Why AT command set?

Frankly, Why do all communication ICs(or at least many of them or most famous or popular) such as Bluetooth or WIFI or GSM or etc support AT command set? why don't they have a simple pin for D/C(Data ...
2
votes
1answer
220 views

Best way to send a simple digital signal wirelessly (close-range)?

I have a small device which powers two vibrating motors. I would like the vibrating motors to be wireless (ie, not actually connected to the device). Here's some more info: Here's the vibrating ...
0
votes
1answer
110 views

what is the digital communication format that the bluetooth module communicates with

I am using ATtiny2313 microcontroller along with a bluetooth module(HC-05) to communicate with my laptop. Heres my doubt, How does the bluetooth module communicate with the laptop. i.e. what is the ...