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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20 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
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1answer
51 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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23 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 ...
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0answers
12 views

Error expectation for channel estimation

I would like to compute the expectation of MSE error in channel estimation. I am using a pilot-aided channel estimation, however in my case, I am using the signals that pilots and data are already ...
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1answer
29 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
39 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 ...
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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
29 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
72 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 ...
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0answers
45 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 ...
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2answers
76 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 ...
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5answers
363 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
81 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
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3answers
336 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 ...
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0answers
38 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
63 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 ...
17
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10answers
4k views

Is there any way to use half-bits?

As most people here know, by using 4 bits, we are able to count from 0 to 15 (0123456789ABCDEF in hexadecimal). But if we were to only count up to 9, we would still be using 4 bits, and the digits ...
2
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1answer
44 views

choice of parity bits for linear block codes

We know that in linear block codes the codeword for a given a message is generated by multiplying the message with the generator matrix G . The generator matrix consists of a sub-matrix which is the ...
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0answers
19 views

A closed form for calculating shaping gain

As we know, in a communication system, we can divide the overall gain into coding gain and shaping gain, but I have not seen any closed form formula for calculating shaping gain, but the definition ...
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0answers
136 views

Transferring data from FPGA to PC (new to FPGAs)

FPGA beginner here. I have a Basys2 FPGA board(i code in verilog) and i wish to make it communicate with my PC. Currently it receives data from a slave device and stores it in an 64 bit register. ...
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0answers
19 views

Error Correcting Codes - Communications

I'm doing a research on the the physical effect of unbalancing the fraction of 1's and 0's in digital communications. Can anyone quote a specific FEC code that adds for example up to 20% overhead to ...
3
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2answers
120 views

TTL Long Distance Transmission Alternatives

I am working on a system that gets data from a sensor via a TTL connection. Currently, the data that is gathered from the sensor is sent to another part of the system via a set of modems. The ...
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0answers
26 views

Variance of background thermal noise wireless communications?

I am new to this forum and hope I can get some help. I have been reading a paper on wireless communications, in this paper a base station with power P=25 is serving a certain user. The user is ...
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3answers
169 views

How to increase range of zigbee?

I have a Zigbee Pro with Arduino whose range is 2 miles as per specifications. But practically its maximum range is only 200 meters. I am using XCTU software. Is there any setting/configuration in ...
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1answer
345 views

Noise level, SNR and BER relationship in BPSK modulation

I would like to know what is the relationship between SNR, noise level and BER in BPSK modulation scheme? Can you please tell me the formula?
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1answer
189 views

What is the difference between 1-bit SDIO vs SPI?

What exactly is the between 1-bit SDIO vs SPI? Does one have advantages/disadvantages over the other?
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2answers
256 views

What is the minimum bandwidth required for a digital communication system using 32-QAM modulation?

If the bit rate of the digital communication system is 'R' Kbps & the modulation used is 32-QAM, what is the minimum bandwidth required for ISI free transmission? My understanding & analysis ...
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0answers
40 views

what is superposition coding?

In the context of multiple access techniques, there is a coding scheme called "Superposition Coding" or particularly "Superposition Coding with Successive Decoding(SCSD)". I surfed the internet, and ...
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1answer
77 views

Difference between spectral efficiency and bit rate

I am reading articles about error correcting codes, facing to a term "spectral efficiency". Due to the context, I guessed that it means "bit rate", but I wonder are these two terms equivalent or not? ...
2
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1answer
172 views

Why it has used BPSK modulation after OFDM?

I am quite new to OFDM modulation. I am reading this from a tutorial. In one of its parts, for showing amplitude variation of the OFDM signals, there is a graph that has used 8 sub-carriers and BPSK ...
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0answers
40 views

What sampling rates will give uncorrelated samples of x(t).considering the mean of the Random Variable 'x' to be zero?

What sampling rates will give uncorrelated samples of x(t) ? Considering the mean of the Random Variable 'x' to be zero. My Thinking: Since the mean of the random variable 'x'is zero,then it will ...
2
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1answer
61 views

How is CPM Modulation Different from PSK?

Continuous phase modulation has been described to me very similar to wikipedia's definition, which basically indicated that the CPM is different from QPSK, for example, because QPSK abruptly shifts ...
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1answer
51 views

How does SMBus receive byte command protocol know what to send?

Im programming an I2C device to act as a PMBus slave. Looking at the SMBus protocols (which PMBus is built on) the Receive Byte command has a format described as follows: ...
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2answers
46 views

parameter that limits data rate in communication

In communication, the maximum data rate that can be achieved is given by Shannon as C=B*log2(1+SNR) bits/sec. Supposing that I've a very high SNR and an infinite bandwidth, then can data be ...
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2answers
46 views

sampling rate, data rate and bandwidth

I'm new to digital communication. How are the terms data rate and sampling rate related to the term "bandwidth" . Am I missing something here?.Can someone explain me in detail? thanks in advance, ...
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1answer
56 views

Group delay when using a matched filter

Supposing I have a discrete time signal x(n). when I pass this through an FIR filter h(n), and again pass this result through h(n) again (essentially this is a second order filtering), the group delay ...
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2answers
64 views

Usage of complex filters in communication

In the last stage of a communication transmitter, at the front end a filter is used to eliminate unwanted signals from other frequencies. As far as I read in literature, are these filters "real" ...
0
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3answers
88 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 ...
1
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1answer
103 views

How do data and address strobes cause input to be latched?

Often in digital systems when multiple components communicate with each other they use strobe signals. Among these are data and address strobes. The strobe signal being asserted means that the data or ...
2
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2answers
102 views

Circuit to throw out 1st bit of every 17-bit sequence?

I have a system that currently uses two Maxim DS1867 digital potentiometers in a daisy-chain configuration. In a new addition to the system I would like to use a new digital potentiometer part like ...
0
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1answer
68 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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0answers
45 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 ...
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0answers
54 views

Difference between “user” and “layer”

I am new to multiple access communication theory. I read some articles on LDS, and I thought that "layers" is a term used for "users" (In another language I thought that for example when we say "we ...
4
votes
3answers
169 views

Why interfaces and buses gets faster with every version if they are physically the same?

An interface or computer expansion bus gets faster with every version eg. PCI express 1.0 is 4GB/sm, PCI express 2.0 is 8GB/s, PCI express 3.0 is 16GB/s. I understand that things like microprocessors ...
1
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2answers
54 views

Spreading vector

I am reading an article that is about CDMA. In that article I encountered a term "spreading vetor". I searched some books such as Proakis and Gallager to see what it means. I even surfed internet for ...
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3answers
157 views

What exactly does a 10-transistor XOR gate look like?

I need a schematic for a 10-transistor xor gate, I have searched everywhere and I see 8, 12, 6, but I can't see 10. What does it look like in a transistor like picture?
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0answers
67 views

Would my project be affected by lack of a filter?

I have chosen to do a final project, I will be transmitting bits using a wien bridge oscilator, I want a 160 MHZ sine wave and I have chosen values for it. I have chosen the AD8041 op amp because it ...
0
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1answer
59 views

RF Solutions ZULU module

I am trying to set up a remote battery voltage checker that will radio the voltage read from the battery to a computer. I went for the ZULU module (by mistake as I should have brought the ZULU-M ...
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0answers
130 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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49 views

How to generate random fading variables using Nakagami-M distributions

I am trying to write my own mat-lab code to generate Nakagami random variables, As we know due to multi-path propagation we have random attenuation and delay. I have a signal coming out and I want ...