Questions tagged [multirate]
The multirate tag has no usage guidance.
63
questions
0
votes
1
answer
40
views
Resampling n timeseries datasets with different sampling frequencies
I am currently working on an IoT project that uses datasets from different sensors with differing sample rates fs = (1s, 30s,...). I combine this with API data <...
1
vote
1
answer
82
views
Multirate systems - downsampling
As my teacher explained the process in class, I wanted to write a MATLAB code for learning purposes that downsamples a signal with a downsampling factor of L. Here's the code I wrote and the output ...
- 103
0
votes
1
answer
61
views
What's the advantage of the multirate filter banks?
Slower clocks mean lower power consumption, any other benefits?
Could the multirate filter be more sharper than the single-rate filter?
Previously, someone asked the similar question, but the answer ...
- 11
1
vote
1
answer
69
views
Why is it said to be alias free in such a multirate system?
Page 246 in multirate systems and filter banks by P. P. Vaidyanathanm.
The sampling in the first stage should have brought the aliases already, why does the author claim that it is an aliaa-free ...
- 11
4
votes
1
answer
92
views
Room Impulse Response Domain of Sparsity
I have been studying the problem of room impulse responses (RIRs) interpolation for a couple of months. I am trying to use compressed sensing to reconstruct (at best) the sound field in the room with ...
- 66
0
votes
1
answer
120
views
Sample rate change using Lagrange interpolator
I'm trying to understand how to make Sample rate change by a non integer factor say $K=1.0012$
In real hardware I will be using cubic polynomial but for now I have chosen a linear interpolator. I have ...
- 45
0
votes
1
answer
204
views
Is the following system LTI and what is its purpose?
Above is a block diagram of a discrete-time system $T\{x[n]\} = y[n]$. Here, $h[n]$ is the impulse response of an arbitrary LTI system.
Firstly, is this overall system LTI? I don't think so because ...
- 1,593
2
votes
1
answer
367
views
Cascade of Downsample and Upsample
Consider a cascade involving a downsampler (factor $M$) and an upsampler (factor $L$). For the sequence
$$x[n] \rightarrow D \xrightarrow{{v_{1}[n]}} U \rightarrow y[n]$$
where $D$ denotes ...
- 403
1
vote
1
answer
300
views
Multirate Control System Transfer Functions
I'm interested in oversampling the inputs to a digital controller to increase the SNR of the input process variable signal. I've read on this site and in articles like the one below that it is not ...
- 296
0
votes
0
answers
874
views
Efficient CIC Decimation Filter in C
Does anyone have advice on efficient CIC Decimation filter implementation. I designed a basic 4th order CIC filter with a 64 decimation ratio in C (below).
I am currently testing this on a Sharc SC589 ...
- 1
1
vote
0
answers
343
views
Z Transform of M-Fold Decimation
I know this is probably a common question, but after some searching I think that my version of the question is slightly different -- apologies if this is a repeat. I have seen that it is inaccurate to ...
- 11
-1
votes
2
answers
326
views
Decimation: how to preserve frequency content that lie above half the decimated sampling frequency?
I know that with three steps:
complex demodulation
lowpass filtering
decimation
we are able to select frequency contents in a band with reduced sampling rate. But this method only allows frequency ...
- 379
3
votes
2
answers
338
views
Getting error while performing upsampling of an audio signal processing using low pass filter in python
I want to perform upsampling of an audio signal introducing zeros between samples to create a longer signal with factor of N=2. The sampling rate is 44100Hz, time = 5sec.
...
- 31
0
votes
0
answers
104
views
Hardware implementation of multi rate FIR filter
I have designed a multi rate fir filter in MATLAB and I want to implement it in verilog.This is the block diagram.
Total number of taps are 391. Is there any way to automatically generate verilog ...
1
vote
1
answer
201
views
Direct and Transpose Polyphase Multirate Processing
Polyphase implementations of upsampling/ interpolation and downsampling/ decimation, after having invoked the Noble identities, are presented as follows (taken from Proakis):
(Three-Channel Polyphase ...
- 11
0
votes
1
answer
97
views
Aliasing Issues in Sub Band Coding
The general structure of Sub-Band Coding (SBC) is shown below:
The diagram shows that after each of the analysis filters, decimation is performed by a factor M which corresponds to the number of ...
- 488
0
votes
1
answer
173
views
Perfect reconstruction in two-channel filter bank
[from Discrete-time Signal Processing by Oppenheim and Schafer, 3rd ed.]
I was not able to prove this:
If the analysis and synthesis filters are ideal so that they exactly split the band 0 ≤ |ω| ≤ π
...
- 335
1
vote
1
answer
336
views
Downsampling after a highpass filter
Question: The following sentence is not clear to me (especially why down-shift occurs). Could someone explain it please?
On the other hand, downsampling the output of the highpass filter down-shifts ...
- 335
0
votes
1
answer
195
views
Interpolated FIR filter (from Oppenheim and Schafer's Discrete-Time Signal Processing, 3rd ed)
[from Discrete-time Signal Processing by Oppenheim and Schafer, 3rd ed., p.196]
Two questions:
In this context, the filter with system function represented by Eq. (103) is called an interpolated FIR ...
- 335
1
vote
1
answer
178
views
Group Delay of Mulitrate system
how do I find the group delay of multirate system.(sample rate converter) , IIR non-linear phase filter
Say decimation by 2 (with lpf) = tf1(num,den)
then again decimation by 2 (with lpf) = tf2(num,...
- 105
0
votes
1
answer
464
views
What are the 'phases' in this 2D scaler filter
I am pretty new to DSP and have been looking at how image scaling is done in hardware. I and came across a 2D scaler core for an FPGA here. I have read up a bit about polyphase filters, but am ...
- 3
1
vote
1
answer
192
views
Where is the mother wavelet defined in the Fast Wavelet Transform?
Referring to the Fast Wavelet Transform, this transform is implemented as a QMF filter bank. This algorithm consists of high/low pass filtering and subsampling. However, a wavelet transform is ...
- 902
0
votes
0
answers
251
views
What is the multiplication rate in FIR filter
Consider a system implementing a rational sampling rate change by 5/7: for this, we cascade upsampler by 5, a lowpass filter with cutoff frequency pi/7 and a downsampler by 7. The lowpass filter is a ...
0
votes
1
answer
870
views
Decimation FFT Result
In my Signal Processing class we just learned decimation however after messing around in Matlab trying an example of decimation, I just can't understand what's happening.
I get the introducing twi ...
- 37
-1
votes
1
answer
369
views
How to figure out number of multiplications in rational sampling
I am trying to understand the following:
Consider a system implementing a rational sampling rate change by $\frac{5}{7}$: for this, we cascade upsampler by 5, a lowpass filter with cutoff frequency $\...
- 109
1
vote
0
answers
84
views
When is it possible to swap expander and compressor?
In the figure below I want to know when is it possible to swap expander and compressor so that the outputs remain the same?
I know in general it's not possible to interchange because neither expander ...
- 350
0
votes
1
answer
93
views
Save computational burden by calculating the output of decimate filter at output rate?
I read in a book that the output of a decimate filter can be calculated at output sampling rate. In this way the number of filtering operations can be greatly reduced. But I am wondering how to ...
- 379
0
votes
0
answers
1k
views
Using FFT for implementing a filter bank
I am trying to use Fast Fourier Transform (FFT) for decomposing an audio signal into 8 sub-bands according to this link but the problem is the frequency response of the result contains only the first ...
- 51
1
vote
2
answers
840
views
Decimating Polyphase Filter in Simulink
I have read many of the articles on the website regarding a polyphase decimating filter structure. I'm sure we are all familiar with the typical image shown in Fred Harris Multirate book and many ...
- 29
3
votes
1
answer
806
views
What’s a good book on multi-rate dsp?
Was Studying a dsp design recently with many decimation and interpolation filters, and was wondering if there is a recommended book specifically on the subject of multi-rate dsp? Preferably a book ...
- 203
1
vote
3
answers
298
views
Upsampling with time offsets
Suppose I have done 4x oversampling for a continuous time signal, but the successive sampling times have a linearly increasing offset. Specifically, the samples with indices {4k; k=0, 1, 2,...} are ...
- 41
1
vote
0
answers
123
views
Using a Multirate FFT system to analyse audio
I am trying to implement a multirate fft system to try and achieve frequency windowed analysis of audio.
Say I have managed to get an impulse response of a system. This impulse may be say one ...
- 159
1
vote
2
answers
378
views
Drawbacks of upsampling using polynomial interpolation
I've come across an upsampler that uses polynomial interpolation and no filter. What are the drawbacks to this? I looks more efficient than filtering.
- 11
0
votes
1
answer
330
views
DTFT of even and odd samples
Here to find DTFT of $h(2n)$ they have scaled omega, while in RHS to find DTFT $x(2n+1)$ they didn't, why is that?
- 3
1
vote
1
answer
59
views
Polyphase components Spectrum formula in Discrete time
I am trying to understand the meaning behind some of the components of the formula for polyphase components in discrete time. Note that $\Omega$ indicates discrete in this notation and the formula is ...
- 13
1
vote
0
answers
46
views
Converting the equalizer coefficients from VSA at 2 sample/Symbol to 1.5 sample/Symbol
I was looking for some feedback on conversion of equalizer/filter coefficients at different sampler rate.
Problem Statement:
We have built a transmitter system whose output is at 1.5 sample/symbol (...
- 11
0
votes
1
answer
121
views
What does it mean for a Wavelet transform to commute with translations?
Referencing this article here https://arxiv.org/pdf/1203.1513.pdf
It states "A wavelet transform commutes with translations, and is therefore not translation invariant". Now I understand why it is a ...
- 902
2
votes
1
answer
124
views
Understanding sampling rate conversion
I am a little bit confused about the concept of sampling rate conversion. Consider the following question:
Wideband telephony signals are sampled at a sampling frequency fS1 = 16kHz. To process these ...
- 467
0
votes
0
answers
145
views
Sampling rate conversion and polyphase decomposition
Can someone please explain the answer to this problem:
The sampling rate of a baseband signal shall be converted from 5 kHz to 7.5 kHz using the efficient polyphase implementation with a 'rotating' ...
- 467
1
vote
2
answers
851
views
Reversing the order of up and downsampling
When we are dealing with the problem of changing the sampling rate by a noninteger factor like L/M, we first need to the do the upsampling, and then the downsampling.
My question is that under which ...
- 467
1
vote
0
answers
410
views
How should I modify my filter coefficients for the filter to be unaltered, when I change my sample rate
I am guessing this is a commonly encountered problem, but I am lost on how to really solve it.
I have FIR filter coefficients that are used to match the frequency response of data sampled at 3 kHz. I ...
- 129
1
vote
2
answers
1k
views
Polyphase Analysis Filter Bank
I have a question regarding the polyphase DFT filter bank implementation in this page. (https://cnx.org/contents/Peqc-TK2@16/Uniformally-Modulated-DFT-Filterbank)
In figure 2, to analyze the kth ...
- 161
1
vote
2
answers
73
views
Decimator effect on wide sense stationary input
I've seen that the output of a decimator when a WSS process is passed through remains WSS. I am not able to immediately see why this is. What is a good explanation of why the signal maintains ...
- 11
4
votes
2
answers
2k
views
What would be the effect of repeating samples in time domain on frequency domain?
Consider the operation of up-sampling a signal n times by repeating each sample n times in the time domain. What would the frequency domain response of the resultant signal be like given the frequency ...
6
votes
3
answers
1k
views
Unscented Kalman Filter - Multiple Consecutive Measurement Updates
In trying to implement an Unscented Kalman Filter (UKF), I have come across the issue of what to do when my measurement signals come in at a different rate than my control inputs, which I use in the ...
- 73
3
votes
1
answer
157
views
How to undo dynamic Doppler effect by software?
I have a signal affected by Doppler effect. In general, the Doppler effect changes the scale of the time and frequency domains. So, to undo this phenomenon, I am using a sampling rate converter. Two ...
- 530
0
votes
1
answer
1k
views
Sampling multiple sensors at different rates
I have a question regarding how best to sample data from multiple sensors when they are all updating at different/changing rates. I am new to data acquisition so please bear with me. For my Master's ...
0
votes
1
answer
249
views
Multirate Signal processing for matching DAC of the SDR
I have been breaking my head for a long time. Please help with this..any input would be helpful!
I am trying to implement a OFDM system using SDR (USRPN210 for Transmitter and USRP2 for receiver) ...
2
votes
1
answer
249
views
Advantage of complex filtering in multirate applications
I've seen it mentioned in passing in various papers on signal processing and filter design that complex FOR filters can be more efficient when it comes to multirate applications. However I cannot ...
- 81
1
vote
1
answer
408
views
