What is Digital communication: Definition and 12 Discussions

Data transmission and data reception (or, more broadly, data communication or digital communications) is the transfer and reception of data (a digital bitstream or a digitized analog signal) over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication channels, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal.
Analog or analogue transmission is a transmission method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code (baseband transmission), or by a limited set of continuously varying waveforms (passband transmission), using a digital modulation method. The passband modulation and corresponding demodulation (also known as detection) is carried out by modem equipment. According to the most common definition of digital signal, both baseband and passband signals representing bit-streams are considered as digital transmission, while an alternative definition only considers the baseband signal as digital, and passband transmission of digital data as a form of digital-to-analog conversion.
Data transmitted may be digital messages originating from a data source, for example a computer or a keyboard. It may also be an analog signal such as a phone call or a video signal, digitized into a bit-stream, for example, using pulse-code modulation (PCM) or more advanced source coding (analog-to-digital conversion and data compression) schemes. This source coding and decoding is carried out by codec equipment.

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  1. A

    Engineering Digital Communications: Bit Error Rate (BER), C/N, Constellations

    Problem Statement: I am not quite sure how to approach this problem and would appreciate the help. I how the C/N is closely related to the SNR (Eb/N0), but the question does not give the bandwidth or data rate for me to use the formula above. From the constellation diagram, my guess is this is...
  2. CMW328i

    Noise Modelling - Digital communication systems

    Hi all, Teacher here looking for some guidance. I'm teaching a class that I took myself a few years back, and I'm looking at my solution to a problem but I have a random value in my answer (which I know to be correct) but I can't for the life of me remember where this value came from! Can anyone...
  3. Awais088

    Why OMP is iterative? Can we find the support in one step?

    In OMP why the 'support' of the received signal is not found in one step, by selecting the $K$ maximum correlated columns of the sensing matrix $A$? where $K$ is the sparsity of the signal. Like in MATLAB [val ind] = sort(A'*Y); %Y is received signal signal_Support = ind(1:K)...
  4. N

    How to compute the location of the antenna when I rotate it?

    Hi group, I have a question regarding to detect the location of the antenna. I read this link: https://en.wikipedia.org/wiki/Plane_wave In the "Complex exponential form" part, the equation: U(r,t) = U0 * exp(j*(k.r - w*t) as the function of location and time U0 = A0 * exp(j*phi) : A0 and...
  5. N

    How to calculate standard deviation from the delay?

    I am trying to calculate the unit vector and standard deviation of the signal. I hope everyone can give me ideas. Here is my scenario: I have 2 rx channels: - f is channel 1 with the length 1x256 complex, then FFT. - g is channel 2 with the length 1x256 complex, then FFT. - from f and g, I can...
  6. N

    How to simulate multipath signals?

    Hi everyone, I am a new engineer just work in the real industry, so I would like to collect more experience from the real project. I am working on the Multipath problem, but I've not done before in the University, and really do not know how to solve it. During the discussion from the...
  7. Simon Hauser

    Very tricky Solar-Module Disconnecting Problem

    My non-ee boss gave me a design assignment I'm not sure is physically possible. I work at a solar panel manufacturing company. He wants me to essentially add a device to the mc4 connectors between modules which would allow disconnecting each module in a string from one another. He wants this...
  8. G

    Frame Synchronisation via Modified Approach to Bit Insertion

    Homework Statement I am currently embarking on a project which requires me to design a system where I can transmit voice over a distance, by inputting an analog voice signal on one end and then recovering the voice which I input on the transmitting end at the receiving end. The general design...
  9. G

    Digital Communication Systems - Autocorrelation

    Homework Statement A white noise process W(t) with unity (N_0/2 = 1) power spectral density is input to a linear system. The output of the linear system is X(t), where X(t) = W(t) - W(t - 1) Determine the autocorrelation of X(t) and sketch it. Homework Equations Let τ denote a time...
  10. C

    Equation of SNR versus sigma square for BPSK

    I would like to know in the following equation (attached) how can I incorporate BER for BPSK? is BER the same as Rc? The equation is relation between SNR and sigma square.
  11. G

    In Digital communication world

    What is the relation between the Energy (E), power (P) and transmission rate (R)?
  12. E

    Question for experienced - digital communication books

    question for experienced -- digital communication books i want name of book for digital communication useful and simple way to present contents that i can study by my self thanks in advance