## Forums Search for: Polyphase

## Complex Matrix Multiplication and Polyphase Filter Banks

inFolks, I'm attempting to write a lo-fi audio effects processor based around a 8 channel polyphase filter bank and I'm having problems with the...

Folks, I'm attempting to write a lo-fi audio effects processor based around a 8 channel polyphase filter bank and I'm having problems with the DFT matrix multiplication. I've designed the filter bank, I implemented it in Matlab and have tested it and I am satisfied there are no horrific flaws in the basic concept. I've implemented the tapped delay line sampling and the decimation/expa...

## Polyphase Filterbanks for Symbol Timing Synchronization

inHi, I am currently reading fred harris' papers mentioned below to implement a timing synchronization in my software DSSS receiver. A. Loop...

Hi, I am currently reading fred harris' papers mentioned below to implement a timing synchronization in my software DSSS receiver. A. Loop Control Architectures for Symbol Timing Synchronization in Sampled Data Receivers B. Polyphase Fitlerbanks for Symbol Timing Synchronization in Sampled Data Receivers Although, I get the big picture behind the idea of implementing timing synchronization...

## 44.1 khz to 48 khz using polyphase

inHi, I am trying to do a 44.1 khz to 48 khz resampling in Matlab, but am coming across a few problems. For this conversion to take place...

Hi, I am trying to do a 44.1 khz to 48 khz resampling in Matlab, but am coming across a few problems. For this conversion to take place the poly phase filters come out like 480/441=(4 x 4 x 10)/(7 x 7 x 3). I have been trying to figure this thing out on paper, like the for the first stage I get 44100 x (4/7), now as I understand it I have to take a 44.1 khz signal upsample it by 4, appl...

## Polyphase filter outputs

inHi, I am almost a complete newbie when it comes to DSP. I've been studying various internet articles a lot over the last week but I still have...

Hi, I am almost a complete newbie when it comes to DSP. I've been studying various internet articles a lot over the last week but I still have some questions that I don't understand. What I'm trying to accomplish is to resample an audio signal to change it's pitch. I don't care if the length changes, I just want to get pitch changes. Since some pitch changes may be somewhat small (notes) I n...

## Problem with IFIR in SRC

inHello, I have implemented polyphase SRC code for ratio of 3/2 (8KHz 12KHz). I am using 396 tap filter, which gives 1584000 [ =...

Hello, I have implemented polyphase SRC code for ratio of 3/2 (8KHz 12KHz). I am using 396 tap filter, which gives 1584000 [ = (24000(Fs)*396)/(3*2)] MAC operations per second (MPS). Now I want to reduce the computations by making use of IFIR method. But I find that the implementation becomes too complicated to be put in a formula that can be implemented on Matlab. Can you please giv

## Polyphase interpolation followed by decimation, do I get original data?

inI am using an 80 tap matched filter to interpolate a signal by 10 times, which splits the coefficients into 10*8taps. After that, I will decimate...

I am using an 80 tap matched filter to interpolate a signal by 10 times, which splits the coefficients into 10*8taps. After that, I will decimate the result by 10 using same filter. Do I get back original data (ignore the delay)?

## SNR estimation

inI need to estimate the SNR (or, even better, the actual signal and noise powers separately) at the output of a matched filter. I have seen...

I need to estimate the SNR (or, even better, the actual signal and noise powers separately) at the output of a matched filter. I have seen various implementations for communications systems using maximum likelihood or based on particular types of signal coding. However my application is a radar type one - the signal transmitted is known (e.g. chirp or polyphase pulse), but after the matche...

## Digital Power Control

inGot an application coming up for a high-efficiency, multikilowatt polyphase power supply that needs scarily fast responses to external...

Got an application coming up for a high-efficiency, multikilowatt polyphase power supply that needs scarily fast responses to external requests. I'm thinking about maybe throwing a C2000 at the problem. It could really simplify keeping my phases in alignment and getting the feedforward through all the paths to match. TI sure makes it look easy, almost as if it's their job to do so. A...

## Polyphase Filters

inHello all, Can someone explain to me the following in Fred Harris' book Multirate Signal Processing for Communication Systems? 1. Chapter 6...

Hello all, Can someone explain to me the following in Fred Harris' book Multirate Signal Processing for Communication Systems? 1. Chapter 6 (page 143 - Separating the Aliases): The inputs to the M-path filter are not narrowband, and phase shift alone is insufficient to effect the destructive cancellation over the full bandwidth of the undesired special contributions (and the next sentence re...

## FIR interpolator

inRecently I run into the problem with a basic task: design of a polyphase set of filters for the interpolation of a signal. The input is the...

Recently I run into the problem with a basic task: design of a polyphase set of filters for the interpolation of a signal. The input is the sampled signal; the output should be the interpolated values spaced at 1/10 of the sample. So, I designed the LPF at 10 x sample rate by the Parks-McClellan algorithm, and then decimated it into 10 subsets of the coefficients. But, although the...

## Sampling rate conversion

inHello, I am designing a sample rate converter from 8khz to 8.4 khz, which gives an upsampling rate of 21 and downsampling rate of 20. I...

Hello, I am designing a sample rate converter from 8khz to 8.4 khz, which gives an upsampling rate of 21 and downsampling rate of 20. I am implementing it using polyphase filters. I have got a filter with cut-off frequency of 21. This means I have 21 filters each of them shifted and upsampled by 21. And finally I cascade the output and downsample by 20. is this the right way of doing ...

## FIR filtering using a lookup table

inHi, Currently I am using a polyphase FIR filter to perform an interpolation. To gain performance I have in mind to redesign the original...

Hi, Currently I am using a polyphase FIR filter to perform an interpolation. To gain performance I have in mind to redesign the original filter with the principle of a lookup table. Does anyone know where I can find some helpful information of how to implement this principle? Regards, Ellegaard

## FMDemod, Phase noise and Polyphase

inHi All, I am trying to debug a FM demodulation noise problem for a FPGA prototype. The output in general looks ok, but the THD+N of a clean...

Hi All, I am trying to debug a FM demodulation noise problem for a FPGA prototype. The output in general looks ok, but the THD+N of a clean 60% modulated signal is only in the mid-40's dB (noticable even by ear), and that is mainly due to a high noise floor. The FM architecture is using the differentiator approach dAtan(Q/I)/dt with [1 -1] as the differentiator. (Phase wrap-around at +/-p...

## FFT upsampling filter

inHi, all: New member here. I did a search, but it seems there is no information related to this topic. What I am doing now is I am trying to...

Hi, all: New member here. I did a search, but it seems there is no information related to this topic. What I am doing now is I am trying to upsample some data points to a much higher sample rate, and to do that, I need a low pass filter after zero stuffing. There are 2 ways to reduce calculation complexity, AFAIK: a. To use a polyphase filter at input sample rate, or b. To use a FFT fil...

## combined arbitrary resampling and match filtering for timing recovery

inHi DSP Guys, Can you please help on polyphase matched filter which is doing arbitrary resampling and timing recovery at the same time...

Hi DSP Guys, Can you please help on polyphase matched filter which is doing arbitrary resampling and timing recovery at the same time ? regards Awan

## Question on channelizer

inHello, I'm a newbie in DSP world and got several questions on channelizer. I recently studied polyphase channelizer and weighted...

Hello, I'm a newbie in DSP world and got several questions on channelizer. I recently studied polyphase channelizer and weighted Overlap-add(WOLA) filter bank. It seems that the only benefit WOLA has is that the number of channels can be not related to the decimation factor. Why is it so beneficial? When each channel is moved to baseband, isn't it desirable to have the minimal sampling freque...

## Re: I'm confused ;) was[Re: ADC limitations for bandpass/IF sampling]

in"Joerg" wrote in message news:qJ_nf.33643$q%.17135@newssvr12.news.prodigy.com... > Hello Steve, > > > This form of polyphase sampling...

"Joerg" wrote in message news:qJ_nf.33643$q%.17135@newssvr12.news.prodigy.com... > Hello Steve, > > > This form of polyphase sampling is much loved by those of a masochistic > > tendency, for the pain and misery it can cause. :-) It is a nightmare to > > get multiple ADCs like this to track over time and temperatures. > > > > Nah, there are situatio

## Multirate filters

inhi all, I am working on polyphase filter bank design. I want some pointers on (i)how to avoid aliasing from other bands? (ii)what are the...

hi all, I am working on polyphase filter bank design. I want some pointers on (i)how to avoid aliasing from other bands? (ii)what are the important steps while considering the design of prototype filter? (iii)How to avoid the amplitude distortion? (iv)How to design filter banks with different passband widths? thanks in advance vanamali

## Halfband filter True or false?

inHello everyone, I would like to confirm that even with a large number of coefficients it is not possible to make a Halfband filter with narrow...

Hello everyone, I would like to confirm that even with a large number of coefficients it is not possible to make a Halfband filter with narrow transition bandwidth? Ex.: Fpass=7MHz(-1dB tolerated), Fstop=8.125MHz with Astop=80dB using Fsampling = 32.5 MHz I tried a few software tools and I couldn't calculate this filter. It seems to me that I have to make it using a polyphase FIR. My go...

## testing a digital filterbank

inHi All, I tried browsing topics on filterbanks on this site so as not to repeat my question. But haven't found any posts that is similar to my...

Hi All, I tried browsing topics on filterbanks on this site so as not to repeat my question. But haven't found any posts that is similar to my problem. I have a 16-channel digital filterbank based on polyphase decomposition. My objective is to find the absolute delay a signal undergoes in one of these filters. To test this, a 10-us square pulse was amplitude modulated by a 50 MHz carrier...