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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1answer
47 views

What protocols are used to distribute internet around the earth? [on hold]

How are intercontinental internet traffic distributed in practice at the HIGH LEVEL. Across fiber cables but with which digital communication protocols, is there a standard or are multiple used in ...
-4
votes
1answer
51 views

How to transfers sensor data through WiFi? [on hold]

I would like to send data from 10 sensors from arduino to a laptop connected to the same wifi network. Can anyone guide me on this task.? Advance Thanks. I have only WiFi no internet.
0
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2answers
46 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
27 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 ...
0
votes
1answer
17 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
60 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
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2answers
75 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
29 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
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2answers
86 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
126 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 ...
-2
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2answers
63 views
-1
votes
2answers
67 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
62 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
79 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
65 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
565 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
43 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
117 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
80 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
88 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. ...
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0answers
22 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
1
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1answer
62 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
84 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
74 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
70 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
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0answers
15 views

MU-LAW COMPANDER for a 10-bit Quantzer … ? how many level will be needed to represent the lowest 30% of the signal for U=0 and U=10

for a 10-bit Quantzer how many level will be needed to represent the lowest 30% of the signal for U=0 and U=10 ? I know it it is u=0(simply no compression) so # of level = 0.3(2^10) which is = 307.2 ...
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3answers
58 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
69 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 ...
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0answers
111 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
66 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, ...
12
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 ...
0
votes
0answers
121 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
72 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 ...
0
votes
0answers
60 views

Transmitting data over Long range ,using a Low Power Circuit

I Have Been Designing a BOT That Would Travel Along the Pipeline And Detect Leakage Using Ultrasound Efficiently,And Locate The Position of Leakage Using A GPS MODULE using the Arduino,I have make it ...
0
votes
3answers
79 views

Sampling Rate Passband Signal

What is the maximum/minimum possible sampling rate for the signal to be full recovered for a passband signal?
2
votes
1answer
86 views

Is it true to add 22 Ohm resistor to help in impedance macthing?

I read somewhere (sorry can't find the source) that adding 22 Ohms resistor on digital line helps in matching impedance. Is it true? Is this a common value? Where should this be added? Near node A or ...
1
vote
0answers
457 views

How to calculate the SQNR of the PCM system in dB?

Assume that the input signal S(t) is sinusoidal with amplitude A and quantized to R number of binary bits, how can I calculate the SQNR of the PCM system in dB? I know that the output ...
1
vote
2answers
285 views

What is The Difference Between PAM And ASK

In Digital Communication can We use PAM in place of ASK The Diagram is Given as The Book Later Talks about Symbols. I Don't Understand, in PAM we don't have specific signal as input like in ASK ...
0
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0answers
24 views

How to measure the QoS of an anlog wireless link

I am working with FSK transmitter and modulator on the 433 MHz band, I am wondering how can I measure the QoS of the resultant link given that The receiver reports the received analog data only with ...
3
votes
1answer
62 views

Storage lifetime considerations for electronics

I am working on a single board computer that I am aiming to last for up to 30 years. It will be based on this design, with a lm7805 voltage regulator circuit and address + data line LEDs. I am ...
0
votes
0answers
111 views

Mueller Muller CDR

For a clock data recovery in a reciever a phase detector is used. In my case I want to understand how the Mueller Muller CDR works. And also what its advantages and disadvantages are. The ...
0
votes
1answer
41 views

Probability of receiving a fixed bit sequence in a binary symmetric channel

What is the probability of receiving 1111 irrespective of what was transmitted? \$0.1^4 + 0.9^4 = 0.6562 \$ I am not sure about my answer because I think in my ...
1
vote
2answers
70 views

Outputting raw bitstream via USB

I am extremely new to this and I'm learning by building stuff myself so please let me know if this is too vague and I'll elaborate if I can. I'm sure this is something very simple, but can't figure ...
15
votes
3answers
3k views

How can over 24 GHz communication be possible?

I read the article Google wants the US' wireless spectrum for balloon-based Internet. It says to use over 24 GHz frequency spectrum for communication. Is it ever possible to generate that high ...
0
votes
0answers
38 views

Implement Automatic Gain control for 16 QAM

How can I implement an automatic gain control for 16 QAM modulation in Matlab preferably without channel estimation (trial and error may be).
1
vote
1answer
109 views

Digital I/O pins connections between IC

I want to ask how is right to connect enable in ICs and digital communication between ICs. Take for example this: want to ask about this 3 examples: Should I use a resistor and how I choose it ...
1
vote
0answers
81 views

How do I draw M-PAM curves of Channel Capacity Vs SNR?

I've seen the following figure in several different articles: (this one was taken from here) I understand that channel capacity of the Gaussian signal is ...
1
vote
2answers
81 views

Monitoring serial communications between two PCBs?

Someone was asking me if it would be possible to monitor the serial communication between two PCBs and output something that is readable. The PCBs are part of an automatic door system - I'm not sure ...
3
votes
6answers
495 views

Implementation and usage of gray code?

Generally and briefly, are there any direct application of gray code in electronics? If so, what are they?
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2answers
95 views

Is it allowed to stop and restore I2C transmission?

Is it allowed to stop and restore I2C transmission? I would like to stop it in different periods of transmission and then after for example 500ms restore it to the state when it was stopped. I'm ...