## interpolation accuracy, oversampling and fractional interpolation

Started by in comp.dsp15 years ago 30 replies

Hi all, Interpolation of a sampled signal x(n) to generate an up-sampled signal y(n) can be represented mathematically as: y(n) = x(n/L)...

Hi all, Interpolation of a sampled signal x(n) to generate an up-sampled signal y(n) can be represented mathematically as: y(n) = x(n/L) /* here L is the intrpolation factor. Regardless of the type of interpolation, if we increase the value of 'L' weather it will increase the accuracy of interpolation process? Whats about the fractional Interpolation/Decimation factors how to deal wi...

## please recomend algorithm for image surface interpolation?

Started by in comp.dsp18 years ago 3 replies

Dear all, I am thinking of treating nature image like surfaces, suppose somehow there are some missing pixels in this image, and I want to do...

Dear all, I am thinking of treating nature image like surfaces, suppose somehow there are some missing pixels in this image, and I want to do surface interpolation to reconstruct the missing pixels. Which surface interpolation algorithm can do this job best? I hope this surface interpolation approach will be a lot better than bilinear interpolation, or separable interpolation, am I right? ...

## Farrow interpolation in QPSK synchro

Started by in comp.dsp14 years ago 7 replies

Hi, I've designed a QPSK bit synchro with Gardner algorithm working with two sample by symbol I've got a Farrow interpolation filter with...

Hi, I've designed a QPSK bit synchro with Gardner algorithm working with two sample by symbol I've got a Farrow interpolation filter with simple linear interpolation If the two input sample of the Farrow filter are 0.5 then 1.0, the interpolation give 0.75 (good) but iof the two samples are 0.75 and 0.75 the interpolation give 0.75 (bad the good interpolation is 1.0) so I think I ...

## Interpolation Jitter

Started by in comp.dsp16 years ago 1 reply

Hello Forum, With reference to FM Gardners article "Interpolation In Digital Modems---PART1: Fundamentals", I have a query regarding the term...

Hello Forum, With reference to FM Gardners article "Interpolation In Digital Modems---PART1: Fundamentals", I have a query regarding the term JITTER. Under the heading "Interpolation Jitter" the author states that " Athough the kth interpolation is computed FOR a time kTi=(mk+uk)Ts, the interpolant is actually delivered coincident with a clock tick no earlier than (mk+1)Ts. Therefore the out...

## Convolution-based image interpolation

Started by in comp.dsp15 years ago 33 replies

I'm looking forward implementing image interpolation in one dimension at once, however I don't really know how to do it. Linear interpolation...

I'm looking forward implementing image interpolation in one dimension at once, however I don't really know how to do it. Linear interpolation doesn't fit me good, I need something better, more like cubic spline interpolation, but the only problem that well implementing it doesn't sound like such an easy thing (I will if I have to, but it definitely won't be my first choice for that precise ...

## Karhunen Loeve interpolation?

Started by in comp.dsp14 years ago 4 replies

I had the idea to try interpolation based on KLT. I tried searching for this with 4 search engines and only found one paper that mentions this...

I had the idea to try interpolation based on KLT. I tried searching for this with 4 search engines and only found one paper that mentions this concept in passing, but without a citation. Any ideas where I might find out more about such interpolation?

## What is the difference between cubic interpolation and cubic “Spline” interpolation?. How to use it for upsampling purpose?

Started by in comp.dsp7 years ago 2 replies

After considering a couple of advices and suggestions for upsampling techniques here, I finally converged to use the cubic interpolation technique...

After considering a couple of advices and suggestions for upsampling techniques here, I finally converged to use the cubic interpolation technique to estimate the voltage values corresponding to intermediate samples present between the original or previous samples. I know that spline interpolation is basically used for getting smoother curves, but what makes it different from the normal cubic inte...

## Interpolation using IIR

Started by in comp.dsp15 years ago

Hello I'm trying to perform Channel Estimation on an OFDM signal by using various interpolation techniques between pilot symbols. The best...

Hello I'm trying to perform Channel Estimation on an OFDM signal by using various interpolation techniques between pilot symbols. The best method is to implement an interpolation filter (in the time domain, or in the freq domain using FFT). The problem is that in order to achieve a "good" FIR interpolation filter, the filter must be quite long. Because of the long filter length (long ta...

## best method for implementing an SRC

Started by in comp.dsp15 years ago 1 reply

Hi, i would like to know which is the best method for implementing a integer sample rate converter (decimation /interpolation) in terms of...

Hi, i would like to know which is the best method for implementing a integer sample rate converter (decimation /interpolation) in terms of quality. the conversion rates required are (2,4,8,16) both decimation and interpolation.i had tried with polyphase implementation and lagrange interpolation.lagrange interpolation is too spiky and polyphase resulted in flat signal without images. But i wo...

## Interpolation with specified end derivatives

Started by in comp.dsp13 years ago 25 replies

Hi, I need an interpolation between 2 points, where I can specify x1,y1,x2,y2 as usual and also derivatives at both ends. I need it to be...

Hi, I need an interpolation between 2 points, where I can specify x1,y1,x2,y2 as usual and also derivatives at both ends. I need it to be computed fast and accurate. It should be an interpolation with minimal (or small) curvature. Example: we have 2 staight lines in X range 0..4 and 6..10. I want to fill the interval 4..6 with a smooth curve joining both of them. My first idea was to use ...

## Interpolation matrix

Started by in comp.dsp13 years ago 12 replies

I'm trying to define a couple of common signal interpolation/ resampling methods as a matrix operation, i.e. y = W z where, y is the...

I'm trying to define a couple of common signal interpolation/ resampling methods as a matrix operation, i.e. y = W z where, y is the interpolated data vector of dimension m x 1 W is the interpolation matrix of dimension m x l z is the original data vector of dimension l x 1 I've worked out W for linear and nearest neighbour interpolation (easy) and I was wondering if more c...

## Linear Interpolation 'error'

Started by in comp.dsp13 years ago 1 reply

Hello People When we perform Linear Interpolation given by the formula below y(n+v)=(1-v)*y(n)+v*y(n+1) where v is between 0 and 1...

Hello People When we perform Linear Interpolation given by the formula below y(n+v)=(1-v)*y(n)+v*y(n+1) where v is between 0 and 1 (http://ccrma.stanford.edu/~jos/pasp/Linear_Interpolation.html#12296) Is there anything like interpolation error? I mean what we do in MMSE. Your guidance will be really appreciated. Thanks Chintan

## compare of two interpolation method

Started by in comp.dsp15 years ago 2 replies

Hi all, As I know there are two interpolation method: 1. As many DSP book said, pading (L-1) zero points into space between...

Hi all, As I know there are two interpolation method: 1. As many DSP book said, pading (L-1) zero points into space between two primitive samples, then lowpass filter it. Then we get the result. 2. linear cubic langerange interpolation. What is difference between those two method? Which has better performance? As my understanding first method alwa...

## An interpolation question

Started by in comp.dsp16 years ago 18 replies

Hi Guys, I was re-thinking an interpolation topic and wondered if any of you have looked into something. Ya' know how we usually...

Hi Guys, I was re-thinking an interpolation topic and wondered if any of you have looked into something. Ya' know how we usually implement interpolation (by an integer factor) by inserting zero-valued samples in between some original time sequence, and then we pass the "zero-stuffed" sequence through a lowpass filter whose output is the desired "interpolated" sequence? Tha...

## Interpolation noise when we resample the irregularly sampled data regularly

Started by in comp.dsp17 years ago 5 replies

Hello to all, Dear i am trying to resample the irregularly sampled data regularly, in order to apply the standard spectrum analysis...

Hello to all, Dear i am trying to resample the irregularly sampled data regularly, in order to apply the standard spectrum analysis techniques on it. For this purpose i am using linear interpolation. But there exist interpolation noise, so kindly tells me the methods to reduce the interpolation noise. I shall be thank full to you for your Help. Regards. Qaisar This message was...

## Interpolation and decimation

Started by in comp.dsp18 years ago 44 replies

Hello, i am looking for decimation and interpolation technique in order to, given a sampling rate fs, obtain a new sampling rate like...

Hello, i am looking for decimation and interpolation technique in order to, given a sampling rate fs, obtain a new sampling rate like (a/b)*fs. A way to to do is to decimate and then use linear interpolation... Is there some other ways (documents) to do this ? If so, have you got some book or url ? Thanks

## non uniform sampling and interpolation

Started by in comp.dsp15 years ago 1 reply

Hello, In another post I asked about interpolation and sampling and I got some good response. After reading them, I am now interested in...

Hello, In another post I asked about interpolation and sampling and I got some good response. After reading them, I am now interested in non uniform sampling and interpolation. What I am interested is to solve following type of problems: Assuming I have a 1D signal that the value of it is known at n=[1 3 4 6 9 10 15 19]. I want to calculate the values at other points {n=[0 2...

## Two stage interpolation : Optimum Order

Started by in comp.dsp14 years ago

Hello Rick, I worked out the math and here is the solution. For two stage interpolation I = I1 x I2, the optimum value of I1 can be...

Hello Rick, I worked out the math and here is the solution. For two stage interpolation I = I1 x I2, the optimum value of I1 can be given by I1 = (fp + fs + sqrt(I*Fs*(Fs - fs - fp)))/Fs where various quantities are: fp = passband freq in hz fs = stopband freq in hz Fs = sampling freq at the input side. I = overall interpolation ratio. ...

## Interpolation by cubic splines

Started by in comp.dsp16 years ago

Is there any reason why cubic splines are a poor method for interpolation of audio signals such as speech or musical instrument sounds? Also,...

Is there any reason why cubic splines are a poor method for interpolation of audio signals such as speech or musical instrument sounds? Also, once upon a time I had a copy of a paper written by someone (if I recall correctly) who worked for E-mu systems talking about pitch shifting. Again IIRC, the conclusion was that for a given amount of computing power, polynomial interpolation would al...

## Multistage interpolation question

Started by in comp.dsp14 years ago 24 replies

Hi Guys, some days ago "hsquared" posted a question about interpolating an audio signal from an original sample rate of 11025 Hz to 24000...

Hi Guys, some days ago "hsquared" posted a question about interpolating an audio signal from an original sample rate of 11025 Hz to 24000 Hz. As far as I can tell, that means an overall interpolation factor of 320/147. I played around a little bit, using MATLAB, with this notion of interpolation by 320. As you can imagine the lowpass filter, following the upsampling (zero stuff...