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noise reduction with long fft's

Started by apchar1 in comp.dsp3 hours ago 4 replies

There's a statement in Smiths The Scientist and Engineer's Guide to Digital Signal Processing about the effect of fft length on noise. In arguing...

There's a statement in Smiths The Scientist and Engineer's Guide to Digital Signal Processing about the effect of fft length on noise. In arguing the virtues of averaging multiple short fft's instead of one long fft he says "Longer DFTs provide better frequency resolution, but the same noise level." But thats not true is it? The noise level of an fft rises with the sqrt(N). The signal grows wit...


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

Started by rishisoni in comp.dsp22 hours ago 1 reply

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...


Shameless plug -- control systems talk in San Jose, September 14th-18th

Started by Tim Wescott in comp.dsp1 day ago 5 replies

In case anyone has been dying to attend one of my talks (or send an associate), I'm now hooked up with a company that presents seminars. ...

In case anyone has been dying to attend one of my talks (or send an associate), I'm now hooked up with a company that presents seminars. Basically, they do all the work that I absolutely dreaded doing to put my seminars on a firm business footing, and I just do the stuff that I do really well. I know this is self-promotion, but I've been contributing to all three of the groups I'm cr...


Joint Kalman Filter vs. Dual Kalman Filter

Started by Anh Tuan Phan in comp.dsp2 days ago 1 reply

Hello all, Could you please help me to evaluate the advantages and disadvantages of Joint Kalman Filter and Dual Kalman Filter, and a...

Hello all, Could you please help me to evaluate the advantages and disadvantages of Joint Kalman Filter and Dual Kalman Filter, and a comparison of the two methods. Thank you very much, Anh Tuan.


Polynomials - Interesting

Started by Anonymous in comp.dsp3 days ago 11 replies

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...

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...


Low pass filters in the time domain?

Started by tomb18 in comp.dsp3 days ago 17 replies

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...

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...


Kalman filter to smooth accelerometer signals using rotation matrix

Started by sia4uin in comp.dsp4 days ago 4 replies

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...

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

Started by smc123 in comp.dsp5 days ago 4 replies

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)...

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

Started by tomb18 in comp.dsp6 days ago 16 replies

Hi, 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 ?

Started by Usjes in comp.dsp7 days ago 13 replies

Hi, 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...


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