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

learn more… | top users | synonyms

0
votes
1answer
31 views

level shifting high speed signals

I have a host of differential signals from a board thats 3.3V. Now, I need to interface it to a board that can accept 2.5V. Now, is it possible to use a standard level shifter like this ? Is there ...
0
votes
2answers
79 views

What's the standard way to detect a digital signal transition?

The 2-phase dual-rail protocol in the concept of asynchronous handshaking relies on detecting signal transitions. How do we detect a signal transition from LOW to High or HIGH to LOW? What is the ...
0
votes
1answer
30 views

Intermediate Frequency in transceiver? [closed]

When I learn the transmitter and receiver architecture? They have each own heterondyne architecture they use intermediate frequency to upconvert to higher frequency or downconvert to lower frequency? ...
0
votes
2answers
45 views

Can you explain how the 2-phase dual rail channel works?

I am doing research in asynchronous circuits. I got to this section of "Asynchronous Circuit Design A Tutorial" by Jens Sparso which explains handshaking protocols. There are four protocols discussed:...
-1
votes
1answer
33 views

How to calculate the transmission ( channel ) bandwidth in a digital communications system?

Is it the bandwidth ( BW ) of the individual pulse or should I generate a random process and calculate the BW from its PSD. In my class we considered it the bandwidth of the raised cosine when we were ...
1
vote
2answers
58 views

Maximum bit rate of a noise less channel

I am not able to find any source giving reason as to why the maximum bit rate in a noise less channel is twice bandwidth multiplied by log L base 2 where L is number of symbols used. What I came ...
1
vote
1answer
67 views

What bandwidth is needed for an arbitrary digital signal?

I am building a fiber-optic data link, with a laser driver and photodiode receiver. My goal is to transmit data at 50Mbit/s. I'm looking for what bandwidth this would take. Obviously 50MHz would not ...
-1
votes
1answer
29 views

Bandwidth-Data rate relationship

From a Data Comms textbook: These are the approximate square waves (Fig 3.7a and 3.7b): This is where the effect of changes in bandwidth on data rate is determined: The problem is the ...
0
votes
1answer
56 views

On the Channel capacity

If we are told that the instantaneous SNR at a specific frequency \$f\$ is \$\gamma\$ (We do NOT assume that the channel is AWGN but we are only interested in the capacity in bit/s/Hz at this ...
1
vote
1answer
39 views

Is Turbo decoding modulation dependent?

I want to use the BER result of a turbo coded system from an article, but my system is not BPSK (and the article has discussed just the BPSK case). Now I wonder is Turbo decoder, modulation dependent?
1
vote
1answer
26 views

Approximation for high SNR

In Slide 6 of this PDF, it says that the performance of binary signaling is as follows: I can understand the approximation for high SNR in the incoherent FSK and DPSK case, but how do we get the ...
1
vote
1answer
69 views

Voltage level translation

I am working on a Vehicle Tracker project. I have few digital inputs coming from vehicle system & their voltage level is 90V. These should go to Micro controller GPIOs which are @ 3.3V. What are ...
-3
votes
3answers
117 views

Commnication between mobiles which are in range of 100 meters without using any mobile tower for free [duplicate]

Every mobile radiates its signal to its nearest tower during phone call.Then is it possible for two mobiles to communicate with out using any tower with in range of 100 meters or more .If it is ...
-1
votes
1answer
62 views

Finding the repetition rate of output pulse [closed]

I have finals coming up next week and I failed to solve this following problem, any help will be appreciated. An automatic translator, with a capacity of \$10^3 \frac{bits}{sec}\$ converts ...
0
votes
2answers
49 views

Connecting Zynq boards fast and deterministic way

I'm trying to make a cluster with Zynq-7010 boards for a real-time application. One of them will be the master, and it will control eight client boards. The master board will also collect the data ...
0
votes
1answer
46 views

Force sensor reading values Raspberry Pi [duplicate]

I have this force sensor: http://www.robofun.ro/docs/2010-10-26-DataSheet-FSR400-Layout2.pdf I need to connect it to a digitial pin of a Raspberry Pi. In order to do that I want to use a polarized ...
1
vote
1answer
33 views

SNR definition in SIMO system

Consider a SIMO (1 transmitter - several receivers) system in which The receiver antennas are used to obtain space diversity and we have a multipath fading channel between transmitter and each ...
1
vote
0answers
31 views

Why do half-band filters form orthonormal bases?

I'm studying wavelet transforms and ran across this little gem, but I can't visualize why a half-band filter would form orthogonal bases of the original signal and the mother. Any insights would be ...
0
votes
1answer
67 views

Gray coding for 8-triangular signal constellation

I'm trying to find the gray coding for the 8-triangular signal constellation below, but no matter what I try, one of the neighbors always has 2 bits differing. For example, two of the neighbors for ...
0
votes
1answer
83 views

What does “capacity achieving code” mean?

I am an electrical engineer passed several courses in information theory and coding theory, however as I think now, I see that I have not understand the basic ideas in these concepts till now. We ...
0
votes
1answer
73 views

Reuse a microphone (formerly) wired to the digital “General Purpose Input/Output” of a Realtek sound card?

I recently repurposed an old laptop screen (from a Dell XPS L502x) as external monitor, and then made the built-in webcam work without too much fuss. The camera module also has an embedded microphone,...
3
votes
4answers
883 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
46 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
58 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
vote
3answers
79 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
vote
0answers
57 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
123 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
67 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
votes
2answers
76 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
vote
0answers
27 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 ...
-1
votes
1answer
84 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
1answer
95 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 (...
1
vote
1answer
54 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
91 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
676 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
214 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
104 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
vote
0answers
50 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
41 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
99 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. ...
0
votes
2answers
87 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
33 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 'slow':...
1
vote
2answers
295 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
334 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
votes
2answers
92 views
-1
votes
2answers
173 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
77 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
114 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
104 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 pins)....