## Forums comp.dsp

## Low pass filters in the time domain?

inHi, I have an IQ signal that I mix with a complex oscillator to bring signals down to 0 hz. I now need to do a lowpass filter on the signal to...

Hi, I have an IQ signal that I mix with a complex oscillator to bring signals down to 0 hz. I now need to do a lowpass filter on the signal to remove all other signals before demodulating the signal. Currently, I have this working by using a 5 pole butterworth filter with a cut off frequency of 3000Hz. This works nice, and I can get the coefficients from online resources. However, what I reall...

## Polynomials - Interesting

inHere's something you may not know. Suppose you want to expand in a power series a polynomial. Let's take a simple one a0+a1z^-1 Then if...

Here's something you may not know. Suppose you want to expand in a power series a polynomial. Let's take a simple one a0+a1z^-1 Then if you write a lower triangular toeplitz matrix [ a0 0 a1 a1] so that the first column is the polynomial coefficients then it's inverse becomes (1/a0)[1 0 -a1/a0 1] ie the first column is the power series expansion - or division...

## Kalman filter to smooth accelerometer signals using rotation matrix

inHello All First post to this group! I have 3D accelerometer signals which are obviously noisy. I want to use Kalman filter to remove the...

Hello All First post to this group! I have 3D accelerometer signals which are obviously noisy. I want to use Kalman filter to remove the noise. I can also use a moving average filter and it will be fine but how can I use Kalaman filter to smooth these signals? regards sia --------------------------------------- Posted through http://www.DSPRelated.com

## Random Vibration Controller

inI'm looking for some guidance on how random vibration control is performed. I've read that the reference signal is a PSD (power spectral density)...

I'm looking for some guidance on how random vibration control is performed. I've read that the reference signal is a PSD (power spectral density) rather than a time domain signal. And that the feedback from the accelerometer (time block of data) is converted to the frequency domain by an FFT, and compared to the reference spectrum to close the loop. Then an IFFT is performed to produce the driv...

## Audio output distorted with any FFT windowing other than rectangular

inHi, For an experiment i have a simple application that takes a quadrature signal from a radio and then does the following: Complex FFT -> ...

Hi, For an experiment i have a simple application that takes a quadrature signal from a radio and then does the following: Complex FFT -> Inverse FFT -> Cartesian to Polar -> audio out If I tune the radio to an AM signal I can demodulate it perfectly well by this but it depends on how the FFT is processed. In the FFT routine, I apply a window and if it is anything other than a rectangular wind

## Is there another name for Baseline Wander ?

inHi, I am interested in a baseband digital communications system (Gigabit Ethernet). The signal spectrum is baseband and there are...

Hi, I am interested in a baseband digital communications system (Gigabit Ethernet). The signal spectrum is baseband and there are isolation transformers at both ends of the channel (cat5 cable). So one of the channel impairments that the transceiver must deal with is baseline wander. ie if there are a long string of 0's (or 1's) the signal begins to look like DC (0Hz) and this will not pass th...

## Understanding DSP or The Scientist and Engineer's Guide to DSP ?

I'm learning about GNU Radio and software radios in general. However, I just have very rudimentary knowledge about DSP (did a really basic...

I'm learning about GNU Radio and software radios in general. However, I just have very rudimentary knowledge about DSP (did a really basic college course) and the mathematics related to it. I picked up DSP for Communications (related to the DSP course on Coursera), and could not understand the math properly. I want to get started with GNU Radio quickly. So I'm confused which book to start learn...

## Array indexing in Matlab finally corrected after 30 years!

inI was glad to hear that Mathworks has finally corrected their array indexing scheme to start with 0 instead of 1, so they're now compatible with...

I was glad to hear that Mathworks has finally corrected their array indexing scheme to start with 0 instead of 1, so they're now compatible with all the other languages out in the real world. Apparently they knew all along that array indexes actually start at zero, but a bug in the initial release of the code caused the 'off by one' problem. An admission of such a glaring math error would ...

## Demodu-sooners

inWhy are comms professionals concentrating their efforts on demodulators? Wouldn't it be better to get ahead of the game and start designing...

Why are comms professionals concentrating their efforts on demodulators? Wouldn't it be better to get ahead of the game and start designing demodu- sooners? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com

## Acceleration signal and Kalman filter

Hello All Posting here after long time! I have acceleration data along with corresponding quaternions. The goal is to remove the bias...

Hello All Posting here after long time! I have acceleration data along with corresponding quaternions. The goal is to remove the bias from the acceleration by using quaternions. I found an implementation where accelerations ax and ay are converted to Euler angles (Phi and Theta) and quaternions are also converted to Euler angles (Phi, Theta and Psi). Then these Euler angles are pass...