Questions tagged [digital]

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2answers
65 views

Why is the fft magnitude spectra of sine not symmetric?

I thought that the magnitude spectra of real signals was symmetric. When I take the absolute value of the fft of a sine wave the result is not symmetric. There seems to be a peak at the first ...
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1answer
19 views

Understanding Baud Rate

I am new to signal processing and just trying to understand what Baud rate really means. As I understand it, the baud rate speed is really the time that the processor takes when it is ON and when it ...
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1answer
29 views

digital phase lead algorithm

I have two sine signals A and B which are simultaneously sampled at 2500 Hz using ADC. Through oscilloscope, I find that signal B lags A by about 5 degrees. I would like to digitally lead signal B to ...
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0answers
18 views

Hisotgram equalisation error, help with my code

Iam working on implenting a histogram equalisation of an image without using inbuilt functions specifcally imhist and histeq, I have, for the most part understood what do during a histogram ...
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0answers
29 views

Training Fractionally Spaced Channel Estimator and Equalizer

If you are attempting least squares channel estimation with a fractionally spaced channel estimator, do you want the training sequence to also be fractionally spaced or symbol spaced? It looks like ...
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1answer
171 views

polyBLAMP anti-aliasing in C++

How should 4 point polyBLAMP work. It does not really seem to dampen aliasing. I have an floating point digital audio oscillator that makes a +1.0f jump at the end of every period. My question is, ...
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1answer
74 views

Follow up question regarding: “Complex sampling can break Nyquist?”

I'm having some trouble understanding the sample rate limitations when considering a complex baseband signal. I understand (based on the linked SE questions below), the either (1) physically ...
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1answer
46 views

Using Matlab/Simulink to build Reader based on Software Define Radio

I am a student. I want to learn about Software Defined Radio to build a Reader for Saw tag and simulate them on Matlab/Simulink. These bocks below is what I want to build in Matlab/Simulink I found ...
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1answer
48 views

Modulating ofdm in audio spectrum

Trying to modulate audio with OFDM data. My fs = 44.1khz, i'm using 64 sub-carriers, but i'm only using 5 sub-carriers for data, so my bandwidth is about 3.445khz. I'm not sure how to properly write ...
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1answer
34 views

How do I add more resolution / taps to an analog -> digital filter?

(I am trying to create an IIR audio filter that adds reverb to an initial sample) Say I designed an analog filter to model acoustic attenuation based on the following mathematical model: $$ I = I_0 ...
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1answer
87 views

How does cascading low pass modules affect pass band ripples?

This question 10.21 is taken from GATE IN paper 2015. I don't understand the answer given, I mean why is the frequency response at the pass band frequency considered to be $(1-\delta)$, isn't the ...
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0answers
43 views

Noise Shape Digital Filter

My objective is to build a noise shape filter from a given transfer function (in one case) and from a given PSD (for another case). Checking my precedent questions you can see that this argument is ...
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1answer
357 views

BIBO Stability in Z-domain

I'd really appreciate it if someone could please explain to me the condition for a LTI system to be BIBO stable, in z-domain. I have a background in control, and in linear control for example, if we ...
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1answer
95 views

Digital Derivative

I need to calculate the derivative of a digital signal (sinusoidal). In one of the papers they have mentioned Gilbert transformation is used to calculate the derivative. But I have searched in the net ...
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1answer
282 views

Block Diagram for a difference equation

I have this little doubt regarding how to draw a block diagram representation of a difference equation. Let us implement $ y(n) = ay(n-3) + by(n-2)+cy(n-1) + x(n)$ in block diagram where $a, b, c$ are ...
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1answer
59 views

Why are binary signals drawn continuous in time despite being a digital signal

The conventional definiton of a Digital signal is as follows: A digital signal is a signal that is discrete in time and quantized in amplitude. Almost all resources (textbooks, online sources,etc) ...
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1answer
68 views

confusion between frequency and amplitude in digital to analog and vice versa conversion

bandwidth is defined as the difference between the highest frequency and lowest frequency. amplitude is the distance between the, let's call it a crest and a trough, in a wave. cycle is the time per ...
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3answers
81 views

Why must the angle contain $\pi$ for $\cos$ be periodic?

The $\cos(\frac{n}{6})$ is aperiodic, and $\cos(\frac{n\pi}{6})$ is periodic, why? What role does the $\pi$ play? By the way, $n$ must be integer I have seen this question,Why is cos(n/6) aperiodic? ...
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1answer
44 views

Glitches in certain frequencies

I am trying to produce some simple audio waves using WASAPI (Windows Audio Session API). If I skip all the abstractions, my program basically receives a buffer from the API, then writes results of a ...
-1
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2answers
378 views

Amplitude ranges for different bit-depths

In Python, I am using the library Soundfile (which uses the library libsndfile) for digital sound processing. I am working with different sound files coming from different internet databases, and ...
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1answer
86 views

Do integration/differentiation processes work as simple filters?

How these processes are different from simple IIR 1 order filtering, FIR filters in terms of amplitude and phase characteristics?
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1answer
206 views

Second order section digital Bandpass

Does anyone have a ressouce on how I can calculate second order section bandpass coefficients? What I tried allready: I used following formulas from the Book Electronic Circuits (U.Tietze, Ch. ...
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0answers
71 views

Processing digital sound in Audiokit to sound like the 1960's

I am looking to imitate 70's analog equipments sound. I was wondering is there a way to create tape saturation / distortion inside Audiokit? I want to add that and randomized tape crackles and ...
2
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1answer
451 views

Bandwidth and Bit rate

I'm kind of confused about digital transmission. Is the bandwidth occupied by some digital signal the Fourier spectrum of the bit (pulse) format,or the one determined by the bit rate?
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1answer
53 views

Subtract a digital filter from another filter

How to subtract a digital filter from another one, if their lengths are different. How to make the length equal.
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0answers
49 views

How does bandwidth affect a modulated digital signal? [duplicate]

I'm currently reading up on how the lower layers of the ISO/OSI model work and I don't quite understand how broadband communication works yet. Suppose I want to send some data from point A to point B ...
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1answer
917 views

Compare two wave files

I have two .wav audio(stereo) files to be compared. The files may vary in frequency or amplitude or phase shift. How to compute the difference between the wave files in Scilab? The expected output is ...
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1answer
310 views

Comparison using cross correlation [closed]

I have 2 stereo audio files to compare. Comparison of files include change in frequency, amplitude, phase shift Code: ...
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3answers
548 views

Applying Nyquist theorem to digital vs. analog audio quality

I had a recent conversation with a friend about analog vs. digital recordings. He shared his opinion that music recorded by analog techniques is of superior sound quality to music recorded by digital ...
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1answer
652 views

How do I calculate the bandwidth from a waveform?

Suppose I have a waveform $x(t)$ where $x(t) = 5 + 30\mathrm{cos}(2000\pi t) + 10\mathrm{cos}(6000\pi t)$ that is to be uniformly sampled for digital transmission, how do I calculate the bandwidth of ...
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1answer
1k views

difference between GMSK (Gaussian Minimum shift keying) and GFSK (Gaussain frequency shift keying) [closed]

I am unable to differentiate GMSK and GFSK. How do the modulation techniques differ in Tx? How do their receiving techniques differ..?
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1answer
102 views

Galois Field implementation

Just a quick question. What Galois Field is best if you need a minimum Hamming distance of $n$? I want to design a BCH generator polynomial that is acccording to this Hamming distance.
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2answers
338 views

Why is CDMA not enough for wireless communication?

I have a question about CDMA, FDMA and TDMA. I don't understand why we suffer from limited capacity when we have CDMA. I can understand the limitation in FDMA and TDMA, as time and frequency are ...
2
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2answers
1k views

Average bit error and symbol energy

How do you draw decision boundaries given this type of 16-qam constellation diagram, I know that there should be no vacant decision boundary but I can't seem to get it.Also, assuming that the correct ...
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2answers
2k views

Analyzing a 16-QAM modulated waveform?

Okay I'm really confused about analyzing the waveform I generated using 16-QAM on MATLAB... I transmitted a $y = [0 \ 1 \ 2 \ 3 \ 4 \ldots \ 15]$ discrete signal (in order) to ...
4
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1answer
22k views

what's the pass band ripple and stop band attenuation of a digital filter?

Hi i'm a beginner in signal processing i want to know what'sthe pass band ripple and stop band attenuation of a digital filter ? Thanks.
4
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1answer
229 views

Why in Overlap Save Method in DSP output length comes out to be same as input length?

I know that when we do convolution of $x(n)$ (Length $L$) and $h(m)$ (Length=$M$), length of output data comes out to be $L+M-1$, but when we break a large sequence of data and find output using ...
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2answers
67 views

Why the correct probability for a square M-QAM is equal to the square of correct probability of ($\sqrt M$)-PAM?

The question is why: $P_c (\text{square} $ $M-QAM) = (1 - P_{\sqrt M})^2$ where: $P_{\sqrt M}$ is the error probability for $\sqrt M$-PAM signal. Thanks.
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3answers
214 views

Sampling and Reconstructing Digital Signal

Say that I have a digital signal (a bitstream actually) whose output changes every 100 mS. I don't know exactly when it changes relative to my sampling, only that that the next bit to capture appears ...
2
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5answers
313 views

Differentiating between zero and not sending for OOK

How would a trigger works for on-off keying (OOK)? How would it differentiate between not receiving anything and zero?
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1answer
17k views

What is the difference between continuous, discrete, analog and digital signal?

It's my first time studying DSP and I've faced a problem finding a convenient definition. Are the following definitions correct? And if so why there are some resources defining it in other terms such ...
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1answer
57 views

Canonical Rectangular Modulation

http://zone.ni.com/images/reference/en-XX/help/371025N-01/loc_eps_rectangular_modulation.gif I just wanted to make sure that my assumption that in this figure $\phi(t)$ is representing $m(t)$, and $R(...
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2answers
534 views

Detecting which digital number an image represents

I photograph the dashboard of my car every day to register the mileage for work. I use OpenCv to detect the region of the digital displayed mileage, crop to the numbers and match them. The method I ...
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2answers
477 views

Calculation of actual analog input from bipolar ADC's output

I have a $14$-$\textrm{bit}$ ADC which can take $-10\textrm{ V}$ to $10\textrm{ V}$ as input. So, $0$ to $16383$ (digital) represents the voltage from $-10$ to $10$. If I want to get the actual ...
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1answer
224 views

why does the decision boundary change in BPSK? is it true?

I am working on modulation and demodulation of BPSK using python. i made a code for modulation and demodulation,while demodulate i tried to compare my actual data bit stream with demodulated bit ...
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3answers
146 views

Linearizing digital-analog converters

I'm looking at ways to improve the effective resolution of DACs. It seems that element mismatch (i.e. integral non-linearity) is the main contributor to distortion in modern DACs. Apart from ...
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1answer
75 views

Digital Filters deal only with samples, right?

I'm new to digital filters. So I'm trying to get things right and I can't find an explicit answer to my question on the internet. Question: Digital filters only accept samples as input? I mean the ...
2
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1answer
146 views

2D Digital Signal Processing - Applying High Pass on and Image

I have been doing my research on 2D digital signal processing. What I am doing is about noise removal of digital image: Type of noise that I want to remove from an images is like the Gaussian noise ...
2
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0answers
1k views

Simple (Arduino) digital butterworth filter : why do I see oscillations?

I want to filter deviations from an ADC over time (low pass), not very critical. So I first tried exponential averaging, something like y= (7*y+x)/8. That gave useful results, but there is an obvious ...