# Questions tagged [polyphase]

The tag has no usage guidance.

22 questions
Filter by
Sorted by
Tagged with
1answer
41 views

### How to perform convolution using polyphase structure

I am trying to implement convolution using polyphase structure but, how to split input samples among different filter banks is my major doubt. Please explain the same with example?
1answer
35 views

### Coherent averaging of polyphase components of a signal

I want to subsample a multi-band signal to introduce controlled aliasing. My frequency components are uniformly distributed across the spectrum (comb structure) and occupy a relatively narrow ...
3answers
159 views

### The z factor in polyphase decomposition

I'm a beginner in DSP and I'm going through the textbook of Oppenheim's Discrete Time Signal Processing. There are two figures in the text, one which I can visualize, and the other I can't. The first ...
0answers
95 views

### Polyphase resampling delay

I want to implement polyphase resampling. For this, I wrote a script in matlab. The script performs the following sequence of actions: ...
0answers
50 views

### What is the threshold to prefer polyphase channelizer over FIR filtering?

A wideband signal need to be processed to extract several narrowband channels from it. There are two straightforward approaches to do so: For each narrowband channel shift frequency and filter it ...
1answer
31 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 ...
0answers
102 views

### Why do I have to scale filter coefficients during bandlimited sample rate conversion?

I am writing an example for how to perform sample rate conversion using windowed sinc and polyphase filters. Here is the C++ code as a github gist. So far, this works, and I think I have understood ...
0answers
27 views

### Seperation of multi-carrier signal using Square Root Nyquist filter

My goal is to separate multi-carrier to single carrier outputs. I intend to do it using Polyphase FBMC. Each of my carrier is 10 MHz in bandwidth. I have 256 such carrier in the channel. Thus I ...
0answers
58 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' ...
1answer
211 views

### Polyphase decimation filter plot in Octave

I'm using de Soras hiir library for decimation and I'm trying to verify the filter design in Octave. The filter is a polyphase 2x downsampling filter with 96dB attenuation and 0.01 transition band, ...
0answers
70 views

### Polyphase FIR image downscaling

I recently started designing a Polyphase FIR filter in with a lanczos kernel interpolator to resample an image in Python. The goal is to downscale the image using these methods. However, I think I don'...
2answers
241 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 ...
0answers
132 views

### Exploiting coefficients symmetry of a FIR interpolation filter in a polyphase implementation

I'm trying to figure out whether there is a way to exploit a symmetry of a FIR interpolation filter in a polyphase implementation. I know for a fact that we can exploit the symmetry in a normal FIR ...
3answers
322 views

### Fractional Delay using Polyphase Filter

How to use rectangular window design to design a length-9 polyphase filter which delays an input signal by 3/5 of a sample? An expression for the 9 coefficients is required.
1answer
586 views

### 16x interpolation using polyphase FIR - sum of the coefficients

I have an issue with polyphase implementation during interpolation. Lets assume I have 256 taps long FIR lowpass sinc filter. In order to interpolate by a factor of 2 I do use two FIR filters (...
1answer
81 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 ...
1answer
730 views

### Polyphase Filter decomposition. It is not working

So, I want to do a polyphase implementation of a filter bank (I had problems with it since the beginning and I already asked for help to the community in the past, indeed: Norm MPEG-1 Layer III (Mp3) ...
3answers
1k views

### How to implement Polyphase filter?

I am trying to implement the following 4-Tap Polyphase window shown in figure below and used in : polyphase filters- radio astronomy: lecture #8 by Prof. Dale E. Gary on Matlab. I have tried splitting ...
0answers
55 views

### How to initialize shift registers in polyphase filter based resamplers to avoid or compensate for group delay?

I have a signal a = [a(t0),a(t1),a(t2),..,a(tN-2),a(tN-1)] I'm using a polyphase filter based resampler with filter length $L$ of $8$, fixed interpolation rate $I$ of $10000$ and decimation rate of \$...
1answer
371 views

### Understanding spectra in polyphase filter banks

I'm trying to fully understand the spectral effects in a polyphase channelizer / polyphase analysis filter bank. I don't really have a signal processing background, so please excuse some incorrect ...
1answer
284 views

### Relative Computational Complexity for Channelizer Implementations

Suppose I want to separate a broadband input signal into multiple narrow subbands using an FFT-based analysis filter bank. The filter bank uses a prototype lowpass filter and is implemented using a ...
1answer
244 views

### Zero Order Hold with polyphase resampler

I'm trying to design a FIR filter(direct form) the coefficient of which will be used to design a polyphase resampler that does Zero-Order Hold resampling. If the direct form impulse response is ...