# Questions tagged [sinc]

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### Why is the time domain low-pass filter the "sinc" shape?

Consider: I'm looking at low-pass filters, and I see that the time domain representation of an "ideal" filter resembles the shape above whereas the frequency domain is a box. I also get the ...
59 views

### Filtering in time domain vs filtering in frequency domain

The signal is an impulse repsonse. I am filtering the signal using a windowed sinc filter in both frequency and time domain. I am interested in knowing the differences between the two methods and ...
1 vote
94 views

### How can the DCT be used for bandlimited interpolation?

I know the discrete cosine transform (DCT) is used for compression, but can anyone give an example of how to use it for bandlimited interpolation? One way might be zero-padding in the DCT domain and ...
315 views

### java resampling implementation using sinc function

To be as succinct as possible, I've written a Java method that implements resampling of a signal using the sinc function interpolation formula. When I test this code with a simple sinusoid, I'm able ...
66 views

### Intuition for how much ringing a particular filter will induce

I've seen figures in various books about the the tradeoff between aliasing and blurring when using a gaussian-like filter: the narrower it is, the more it cuts off low frequencies and thus blurs it, ...
397 views

### Fourier Transform of impulse train proof in Julius O Smith's textbook

$\DeclareMathOperator{\sinc}{sinc}\DeclareMathOperator{\asinc}{asinc}$I'm trying to follow the proof of the Fourier Transform for an Impulse train given in Julius Smith's textbook. I come across the ...
411 views

### Designing a digital band pass filter with Sinc filter in time domain

I want to design a sinc filter in the time domain (a bandpass filter in the frequency domain). I wrote test code in python to investigate, and would appreciate help understanding it and answer my ...
62 views

### Synthesizing a pure tone in Frequency Domain: can it be done more efficiently?

I came to the conclusion that synthesizing pure tones in Frequency Domain is much less efficient than synthesizing cosines in Time Domain and then computing the FFT. But I suspect this is the case ...
291 views

### Applying Kaiser Window to sinc interpolation

I am trying to apply the kaiser window during sinc interpolation. The following is my sinc interpolation code: ...
779 views

### Odd artifacts after sinc interpolation

I am trying to upsample a signal using sinc interpolation. I have written a way to do this in python. ...
608 views

### Why use sinc function to downsample an image in fourier domain?

I'm very confused about downsampling in image processing and the use of sinc function to do it. I read this post : 2D Fourier downsampling some time ago that talked about my own doubt, that is to ...
358 views

### Convolution of squares / boxcars in functional form

$$\Pi(t/A) * \Pi(t/B)$$ where $$\Pi(t) = \begin{cases} 1,\ -1/2 \leq t \leq 1/2 \\ 0,\ \text{otherwise} \end{cases}$$ How to compute? Derivation/steps optional but welcome. Note: I'm aware of ...
93 views

### Convolve sinc trains

\begin{align} & \mathrm{sinc}(As + .5)\sum_{n=-\infty}^{\infty} \delta (s - n/A)\ \star \\ & \mathrm{sinc}(Bs + .5)\sum_{n=-\infty}^{\infty} \delta (s - n/B) \end{align} How to compute? ...
483 views

### Fractional Frequency Shifting a Discrete Signal in the Frequency Domain

In our current hardware-based signal processing pipeline, we have a time-domain signal $x[n]$ that we want to frequency shift by $f_0$. To do this, we multiply the signal by a complex exponential in ...
1k views

### Impulse response of IIR low-pass filter

(Disclaimer. I have started doing some DSP. The last time I worked with this was in the eigthies. And I wasn't much of a specialist then, either.) Is the impulse response different for IIR and FIR ...
75 views

### Is the ideal reconstruction process BIBO stable?

It is well known that ideal lowpass filter, i.e. the lowpass filter whose impulse response is $h(t) = \text{sinc}(t)$, is not BIBO-stable because $h(t)$ is not absolutely integrable. However, think ...
401 views

### Downsampling an image using sinc interpolation?

I have a discrete image of size $2^N \times 2^N$ which I would like to iteratively downsample to produce a pyramid with image sizes $2^k\times 2^k, \, k=0,\ldots,N$. That is, each subsequent image ...
1 vote
156 views

### How do I confirm that range cell migration correction was done correctly? Is there a way to check this graphically without looking at the signal data?

I am implementing the Range Doppler Algorithm for a Synthetic Aperture Radar project and I am at the step where I must perform Range Cell Migration Correction. This step involves creating a sinc ...
503 views

### Differences in transforming a sinc FIR filter from lowpass to highpass using spectral inversion and spectral reversal

I have designed a lowpass sinc 1023 tap FIR filter with a Blackman window and this works fine. I understand there are then two ways to transform this lowpass filter to a highpass one. One is spectral ...
1 vote
290 views

### Triangular dither - What does it mean to say that an input signal is uncorrelated with the dither

In the oft-cited ADC dithering appnote: Oversampling Techniques using the TMS320C24x Family http://www.ti.com/lit/pdf/spra461, it notes under triangular dither: However, this approach requires that ...
532 views

### Inconsistency Between Analysis and Simulation Results of Fourier Transform of a Sinc Function

First of all, hello. This question is about a problem that I’ve faced during an attempt to obtain both time and frequency responses of a sinc function in MATLAB. The problem is an inconsistency ...
105 views

### Output of a linear time-invariant(LTI) system

I am very confused about one of the questions I received during an exam. How do I solve this question?
1 vote
347 views

### How do I sort out my window sinc low pass filter

I started writing a windowed sinc low pass filter, but I cannot seam to get the code figured out right. I followed these two links http://doctord.webhop.net/Courses/textbooks/Smith_DSP/dsp_book_Ch16....
1 vote
875 views

### Sinc3 Filter in FPGA

I working on FPGA block which requires an Sinc3 Filter for Sigma-Delta ADC coming in. I read about it and Sinc filter, is filter with frequency response of sinc, that means its just a moving average ...
1 vote
4k views

82 views

### how sinc pulses can be used to distinguish different symbols

Let's say we want to transmit a sequence of numbers Using PAM, this sequence is transmitted with the signal $s(t)$ The pulses in $s(t)$ are transmitted at a rate $R_p=\frac{1}{T_p}$. This is called ...
201 views

### Rectangular Pulse Train and Sinc Function

I wanted to ask that in frequency domain the rectangular pulse is a sinc function, so is this sinc function periodic or aperiodic? Also if signals that are continuous in time domain then they are ...
1 vote
277 views

### Convolution of Heaviside function with a sinc low pass, is it band limited?

Is the result of convolution of a heaviside function with a sinc low pass with cut off at fc, say 25khz, band limited ((sin(2 x Pi x fc x i))/(Pi x i))? I've been working it out in frequency domain (...
83 views

### Sinc Low pass and transients

Assume, I am trying to use a 50khz sampling rate for some signal. I don't know what the spectrum of input signal is, so I will have to low pass manually with sinc (theoretical best low pass) to band ...
1 vote
276 views

### How to prove a train of sinc pulses in digital communicaton system are orthogonal to each other?

Consider a train of sinc pulses: $$\phi_n(t)= \frac{\sin(\omega_M(t-nT_s))}{\omega_M(t-nT_s)}\quad; n=0,\pm1,\pm2,\dots$$ $\quad$where,$\quad T_s=\frac{\pi}{\omega_M}$ Now ,in order to show sinc ...
1k views

### How to implement sinc interpolation

I'm trying to write my own high quality audio sample rate converter. I barely know anything about signal processing though so I need help. From what I understand I need to sum together normalized sinc ...
2k views

119 views

### ZOH non ideal sampling loss formula

Hello i am trying to calculate the amplitude loss of non ideal sampling. My signals amplitude is 10 at 70 frequency. When we sample it at Fs=400 we have al 0.511 loss as shown in plot bellow. How can ...
411 views

### Reconstruction using sinc

The signal that I produce above. What is the reason for it to slide to the right? In oversampling at Nyquist rate can I make like below picture ? do you think the signal i produced at nyquist rate is ...
1 vote
1k views

### Convolution Integral of Harmonic Signal (Cosine) with the Sinc Function

I was asked to show that this convolution integral results in the answers also given in the image. Not quite sure how to approach this integral, everything seems to be coupled together. Does anyone ...
33 views

### Impulse coefficient when it does not match the bin index

Assume that I have a N=10 samples with Fs=10. assume in the time domain an unit impulse event happens which should be placed at 3.425 index in time domain. Assume that I could not change Fs or ...