Questions tagged [digital]

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20
votes
6answers
871 views

What does one need to know in order to build a software synthesizer?

For someone who has some experience in software development, loves his synths and knows the [very] basics of digital audio representation, what are the first steps he should follow in order to program ...
11
votes
4answers
52k views

Difference between Digital signal and Discrete signal

I have just started studying Digital Signal Processing. Can someone explain what is the difference between a Discrete Signal and a Digital Signal in simple words? Thanks in advance !
10
votes
3answers
13k views

Digital Distortion effect algorithm

I read the DAFX book by Udo Zölzer about the distortion effect at pages 124-125 and it says that suitable simulation of the distortion is given by the function: $$f(x)=\frac{x}{|x|}\left(1-e^{x^2/|x|}...
6
votes
8answers
9k views

Nyquist Frequency Phase Shift

The figure below shows in dashed lines sinusoidal signals of the same frequency at three different phase shifts. The signals are then sampled such that the sinusoidal frequency is exactly a half of ...
6
votes
3answers
21k views

What is IQ Data?

I have no background in telecommunication. Could anyone please explain to me what is the IQ data in telecommunication? It will be best to explain it with some basic analogies. Many thanks!!
4
votes
3answers
3k views

Digital filters with more zeros than poles

I am having trouble wrapping my head around digital filters with different orders of numerator and denominator. Let me know if any of these points is wrong: All (digital or analog) transfer ...
4
votes
1answer
30k 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
votes
1answer
297 views

Is it possible to do further beamforming on already beamformed data?

I've a circular array of eight FM antennas. I'm doing digital beamforming to form eight beams with the following beam patterns: The objective is to reduce my side lobes even further, and to get ...
4
votes
3answers
216 views

Low analog lowpass + ADC vs High analog lowpass + ADC + low digital lowpass

I'm doing EEG data collection and my amp forces use of an analog lowpass filter before the ADC. I'm fairly sure that I won't be interested in phenomena associated with frequencies of 30Hz or higher, ...
4
votes
2answers
187 views

What Is the Correct Way to Apply Richarson Lucy Deconvolution to Luminance Data?

My question concerns the Richardson–Lucy deconvolution algorithm, which is described in Richardson's original paper. I am interested in applying it in the context of a raw image converter for digital ...
4
votes
2answers
816 views

Spectral images - How do they appear during ADC?

Why is it that spectral images appear? I know they appear for $F_s$, but why those replicas appear, I don't know. E.g., sampling $x(t) = sin(1000 * 2\pi t)$ with a sample frequency of 230 Hz. I know ...
4
votes
1answer
272 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 ...
3
votes
2answers
414 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 ...
3
votes
3answers
87 views

Papers for Teaching an Introductory Course in Image & Signal Processing

I'm preparing a digital signal/image processing introductory course and, besides the theory and practices I want the students to read and discuss a couple of research papers during the last one or two ...
3
votes
2answers
311 views

Ignoring Nyquist

What happens if I ignore Nyquist? I have a 16.368MHz digital signal coming out of a GPS front-end chip. My microcontroller (which is reading that digital stream of data) operates at a maximum of ...
3
votes
1answer
145 views

What is databending and how does it actually work?

http://www.google.com/search?q=databending It is, from what I understand, opening images as audio, applying effects, exporting back as image and voila! glitch-art Example: credit But how does ...
3
votes
1answer
3k views

What is spatial correlation and spatial convolution?

What does the term spatial correlation and spatial convolution mean with respect to digital image processing ?
3
votes
3answers
269 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 ...
3
votes
1answer
3k views

Digital Gaussian White noise signal generation in C++

I am trying to generate a band limited noise signal on a Raspberry Pi. I calculate samples at every 1/48000 sec on the Pi. If I generate normally distributed random numbers as data points at every ...
3
votes
1answer
137 views

How to filter a regular ticking out of a digital (on/off) signal?

I have a digital on/off signal sampled at a regular interval. There was a problem with the sensor that produced the signal which has sometimes caused a regular on/off ticking when the sensor should ...
3
votes
1answer
3k views

Understanding “voltage” and “power” in SNR of a sampled signal

I'm facing a gap in my understanding of when a signal is a "voltage" signal and when it is a "power" signal that I've always managed to avoid resolving until now... First what I think I understand, ...
2
votes
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 ...
2
votes
5answers
383 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?
2
votes
1answer
163 views

Shouldn't the Sampling Theorem imply that there should be no information loss at all after a signal is processed?

I am very, very new to signal processing (only started a few days ago) so please bear with me because I may be missing the big picture. Consider an arbitrary signal $x(t)$ with varying frequency to ...
2
votes
1answer
20k 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 ...
2
votes
2answers
359 views

DAC to Analog Filter to ADC

As the order of filter needed for digital information gets higher, it takes longer to process and requires more memory. Maybe analog filtering could be of use here. I know that the words analog and ...
2
votes
2answers
4k views

Carrier frequency offset (CFO) estimation using cyclic prefix

I understand the cyclic prefix, but in (1) it's said that: "If we consider that the channel effect is minimal and can be neglected. then the phase difference of the CP and the OFDM symbol which the ...
2
votes
1answer
692 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?
2
votes
3answers
93 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? ...
2
votes
1answer
759 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 ...
2
votes
1answer
220 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
votes
1answer
819 views

Creating a digital filter, from Laplace to $\mathcal Z$-transform (zero order hold) to code?

I'm trying to create a digital filter in code(C) but any language is fine. Now I've got an analogue filter that I have represented by an equation in the Laplace domain and I want to try and implement ...
2
votes
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 ...
2
votes
1answer
374 views

Digital Vs. Analog Phase measurement [closed]

I'm working on a Ultrasonic Transducers resonance tracking system. Where phase shift between Voltage and Current is the feedback signal for my system when phase difference is Zero that means system is ...
1
vote
3answers
207 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 ...
1
vote
1answer
130 views

Are there analog re-configurable filters?

I know that we can build a chip (or circuit) or use FPGA to have re-configurable digital filters. But how about analog filters, can we have re-configurable analog filters? thanks
1
vote
3answers
717 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 ...
1
vote
1answer
230 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?
1
vote
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 ...
1
vote
1answer
77 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 ...
1
vote
1answer
521 views

How Radix-8 and Radix-2^3 are related

How are Radix-8 and Radix-2^3 FFT are related? Are they same? I got some more details in IEEE paper by S.He and M. Torkelson, "Designing pipeline FFT processor for OFDM (de)modulation," in Proc. Int....
1
vote
3answers
3k views

Explanation of binning in frequency analysis post-FFT

I am creating an Android app which records sound for t seconds at a sampling rate of 44.1kHz with a buffer size of 8192 (16 bit mono samples). I need to plot a ...
1
vote
1answer
56 views

Discrete signal vs digital signal?

Is there any difference between the two? When we say discrete signal, does it only imply that the x-axis or time is discrete? Or it can also mean discrete amplitudes on the y-axis? Or is the signal ...
1
vote
1answer
173 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 ...
1
vote
1answer
2k 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..?
1
vote
2answers
672 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 ...
1
vote
2answers
2k views

Exact definition of soft bits in digital receiver

At which stage of digital receiver, the bits are considered as soft bits? I am unable to find the exact definition. I have rough idea how soft bits are different from hard bits but in terms of signal ...
1
vote
1answer
4k views

Differential BPSK vs BPSK what are the advantages and disadvantages?

Recently I have come across different variation of the sane modulation techniques. I am quite confused about the advantages of different constellations. In particular, what are the advantages of using ...
1
vote
2answers
1k views

Transmission Bandwidth and Sampling frequency

In LTE standards, for a transmission bandwith of 2.5 MHz, the sampling frequency is 3.84 MHz. I was wondering with this choice, are we violating Nyquist theorem? I found the details in the following ...
1
vote
2answers
101 views

Sampling and Reconstruction of digital signal in Matlab

I'm trying to write a program in Matlab that samples (using Nyquist theorem) and recovers signal. However, I cannot write sampling part for sum of 2 signal. ...