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
21 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
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0answers
10 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
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1answer
50 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. ...
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2answers
65 views

applying for loop

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
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0answers
28 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 ...
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2answers
73 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
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2answers
116 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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2answers
61 views
-1
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2answers
63 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 ...
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1answer
58 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 ...
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2answers
52 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
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1answer
59 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
534 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 ...
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1answer
42 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
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3answers
87 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
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0answers
77 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
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2answers
84 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
21 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
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1answer
40 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, ...
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3answers
81 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
70 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
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1answer
68 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.
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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 ...
0
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3answers
55 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
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1answer
60 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
98 views

Porting Costas Loop from Matlab to FPGA

I have designed a Costas Loop for carrier synchronization in MATLAB, here is my code: ...
0
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1answer
60 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, ...
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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 ...
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0answers
100 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 ...
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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 ...
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0answers
53 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 ...
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3answers
70 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
83 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 ...
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0answers
425 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 ...
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2answers
243 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 ...
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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
60 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 ...
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0answers
98 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
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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 ...
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2answers
68 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 ...
14
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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 ...
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0answers
37 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).
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1answer
103 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
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0answers
72 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
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2answers
79 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
477 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
93 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 ...
2
votes
3answers
819 views

How to read a push-pull output

I recently came across a sensor that had a "push-pull" output. I can't find anywhere how to read such an output: Is it some particular kind of analog output? I would want to read it with the ...
0
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0answers
136 views

SIM900 GSM module power LED on but can't get signal

When I connect my module to power the power LED stays on but I can't get signal LED blinking. I am connecting it to my PC via serial port and using Putty software. I am using a SIM900 Flyscale module. ...
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1answer
147 views

A circuit to prevent parasitic powering of FT232RL by MCU, will it work?

In a previous question I asked how to prevent the MCU TX pin (3.3V when idle) from powering an FT232RL Usb to Serial chip via the TX line: Preventing parasitic powering of FT232RL by ATMega328P I ...