## Forums Search for: Interpolation

## Is this correct method for using interpolation?

inHi all! ...I am curious as to whether I am doing the right thing here or not! ...Im designing a flanger effect, but what is known as the...

Hi all! ...I am curious as to whether I am doing the right thing here or not! ...Im designing a flanger effect, but what is known as the "zipper effect" is occuring when i run my algorithm (using the C6711 DSK). I am confused as to exactly why, because after reading many articles on interpolation, it seems to me like im doing the correct thing! please may anyone have a look and let me know... my f...

## Pilot based interpolation

Hi all, i'd like to ask about pilot based interpolation in channel estimation of OFDM cells. I have a block of reference cells which i need...

Hi all, i'd like to ask about pilot based interpolation in channel estimation of OFDM cells. I have a block of reference cells which i need to interpolate in time and frequency domain. An example : xo....................oxooxooxooxooxooo oo....................ooxoooxooooxoooox ox....................ooxoooxoooxoooxoo xo....................ooooxoooxooooxooo oo....................oxooooxo...

## interpolator

inHi , I was reading a document describing a sample rate converter .It can do a interpolation by a factor 64x(max)...and says that "it can...

Hi , I was reading a document describing a sample rate converter .It can do a interpolation by a factor 64x(max)...and says that "it can generate up to 64 interpolated phases between input samples"..I understand that it can put 63 new values (max-interpolation by 64) but what is this phases b/w samples??and why it is 64 rather than 63... Regards SKM

## Signal Interpolation

inHi I am looking at fixing corrupt audio files by interpolating the wave pattern that should be present in place of the corrupt segment. I...

Hi I am looking at fixing corrupt audio files by interpolating the wave pattern that should be present in place of the corrupt segment. I have been looking at 'cubic interpolation' but it seems to me that this scheme is only useful in interpolating individual sample values, not in interpolating whole missing segments of data. Am I correct in this thinking or is it possible to use this sche...

## Decimation/interpolation

inHi, I have a, maybe stupid, question about decimation and interpolation. Let's say we have a signal sampled at 20KHz, so with an...

Hi, I have a, maybe stupid, question about decimation and interpolation. Let's say we have a signal sampled at 20KHz, so with an useful bandwidth of 10KHz. This is ideally low passed at 5KHz, then is downsampled (decimated) by a factor two. This means taking one sample and discarding the next, or, in other words, taking all the even samples, or the odd ones... Now, in theory taking...

## interpolation filter

inwant to ask please about the following: the functions of designing interpolation filter

want to ask please about the following: the functions of designing interpolation filter

## Cubic Splines and cubic Hermite Interpolations

inHi, I have a question regarding some interpolation methods.. If someone in here could tell me the difference between: a) Cubic Splines and...

Hi, I have a question regarding some interpolation methods.. If someone in here could tell me the difference between: a) Cubic Splines and cubic hermite interpolation methods. b) Is there a difference between cubic hermite polynomials and cubic hermite interpolation. I read through various literatures but, couldnt really understand the difference. I would really appreciate if someone ...

## =?iso-8859-1?q?Discrete_B=E9zier_interpolation?=

inHi, I'm currently trying to find a way to interpolate a 1-dimensional signal using something like B=E9zier interpolation, my main...

Hi, I'm currently trying to find a way to interpolate a 1-dimensional signal using something like B=E9zier interpolation, my main problem being that I don't know exactly what matches to what I want. Basically, the signal that I want to interpolate is a user-created sound envelope in order to modulate a signal with it. Therefore, I consider windowed-sinc interpolation unsuitable due to th...

## LUT and interpolation

It's some time since I happened to be forced to use a LUT and interpolation to implement fuctions that the architecture to be targeted didn't...

It's some time since I happened to be forced to use a LUT and interpolation to implement fuctions that the architecture to be targeted didn't offer or did actually offer but with poor performances. So, out of curiosity, I asked myself what is the most clever way I could come up with to implement, for example, the log function in the compact domain [1,2] for fixed point algebra. So I took...

## Multistage Interpolation - Need help understanding each stage

inFrom scouring this group, I see that someone else is attempting the same thing that I'm trying to accomplish - multistage interpolation of an...

From scouring this group, I see that someone else is attempting the same thing that I'm trying to accomplish - multistage interpolation of an audio signal. Just getting my feet wet with this topic, I'd like to ask you guys a few general qustions. Taking a bandlimited audio signal sampled at 44.1kHz and interpolating by 160 broken into multiple stages (4x, 5x, and 8x respectively), my qu...

## Interpolation/FIR/etc... =]

inHi all! Here's a brief description of my application: -> I'm using a Stratix II FPGA to generate data samples and send them to an external...

Hi all! Here's a brief description of my application: -> I'm using a Stratix II FPGA to generate data samples and send them to an external DAC. -> Data is generated at rates from 1MSPS to 31.25MSPS. -> I've instantiated an Altera FIR Filter to mask shape this data. This filter also does an 4x interpolation With that I get my signal spectrum and several images at Fs, 2*Fs, etc., where Fs=D

## OFDM Trasmitter

Hi, I am trying to design an OFDM trasmitter. My current structure is as follows: IFFT -> Cyclic Prefix insertion on I and Q -> x4...

Hi, I am trying to design an OFDM trasmitter. My current structure is as follows: IFFT -> Cyclic Prefix insertion on I and Q -> x4 interpolation filter on I and Q -> I/Q quadrature modulator -> output to DAC. My question is related to the interpolation filters. The convolution between the input to the filter and the filter impulse response smudges the symbol. For example, if the FFT

## Gibbs phenomenon

inHi! I am working over high quality image processing algorithms (image shifts, image rotation, etc). I am trying to use 1D sinc interpolation,...

Hi! I am working over high quality image processing algorithms (image shifts, image rotation, etc). I am trying to use 1D sinc interpolation, but it produces Gibbs artifacts. Is it possible to modify sinc interpolation in some way in order to reduce these artidacts? Perhaps, it is better to use some other interpolations for the case of sharp edges? I have tried to apply some windows (Hann, La...

## Standard filters for interpolation/decimation?

inI'd really like not to reinvent the wheel for my current hobby project, so I beg of all DSP people out there - what are the standard filters...

I'd really like not to reinvent the wheel for my current hobby project, so I beg of all DSP people out there - what are the standard filters used for 16X interpolation/decimation? Are they windowed-sinc, Chebyshev, Butterworth, or something else? And what are the coefficients, can I find tables of them somewhere? My goal is to create a simple VST guitar distortion plugin which uses non-lin...

## linear interpolation, is it necessary to search for the neighboring points?

inHi all, Let's discuss scalar function y=f(x). I generate a 1-D Look-up table as follows: I sample non-regularly (i.e. not equally spaced...

Hi all, Let's discuss scalar function y=f(x). I generate a 1-D Look-up table as follows: I sample non-regularly (i.e. not equally spaced partition) the x axis into N points. Then, store the y_i=f(x_i) , i=1,...,N into a 1D-LUT. To estimate y_j=f(x_j) for a x_j not in the grids, I use the the linear interpolation. Now my question is that, in the hardware implementation, is it necess...

## Low pass interpolation!!

inHi, I am looking for low pass interpolation filter - C code or pseudo code/algorithm descriptions etc. MatLab has one such function "interp"-...

Hi, I am looking for low pass interpolation filter - C code or pseudo code/algorithm descriptions etc. MatLab has one such function "interp"- the algorithm is described in "programs for digital signal processing",IEEE Press,1979. Unfortunately I do not have the book with me. Could anbody help with online resource. Regards, Santosh

## origin of "Bracewell interpolation"?

inI can across a really old Fortran program with a subroutine that interpolates a 1D array of N samples to 3N samples. It uses a 5-point operator,...

I can across a really old Fortran program with a subroutine that interpolates a 1D array of N samples to 3N samples. It uses a 5-point operator, and the comments describe it as Bracewell method, spline approximation to sinc. I haven't seen this before. Bracewell's 1995 book on Two-Dimensional Imaging had a formula for 6 nearest points. Did he publish a formula for 1D interpolation with 5 po...

## compression knee interpolation

inhowdy, i have a perhaps kind of silly question. i'm trying to program a compressor with a variable knee, expressed as dB above and below...

howdy, i have a perhaps kind of silly question. i'm trying to program a compressor with a variable knee, expressed as dB above and below the compression threshold. given the threshold, knee and ratio, i'd like to compute an interpolation function (preferably a polynomial for speed) that matches the values and first derivatives at the start and endpoints of the knee region. to be a li...

## clocks used in polyphase interpolation scheme

inGreetings, I am trying to understand how the clock domains work during interpolation using the polyphase structure. Does one use 2...

Greetings, I am trying to understand how the clock domains work during interpolation using the polyphase structure. Does one use 2 different clocks during implementation(lets say an interpolate by 2 FIR filter). One at the input and one at the output which is 2x the input clock. IS this correct? or can you just use 1 clock thru out, if the latter is true, how is this done?. Th...

## interpolation filter

inI was given a project that uses a 150 some point interpolation filter that upsamples digitized signal by 4. The digitized signals are sampled at...

I was given a project that uses a 150 some point interpolation filter that upsamples digitized signal by 4. The digitized signals are sampled at rate of 6.4 uS. I do not know the band checking characteristics of the filter, only thing I know by looking at the code is that it upsamples by 4. No other document. One of my tasks is to have sample rate changed to 12.8 uS. Obviously, the interpo...