raeldor's articles:

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FFT vs DCT 36 30 (9/26/2011 2:29:15 PM) comp.dsp Hi All, I'm trying to understand the differences between FFT and DCT and was hoping someone may be able to help me with a couple of questions. 1. Is DCT basically the same as an FFT that operates on real numb... Raeldor

DCT Code 1 58 (9/11/2011 10:25:46 PM) comp.dsp I'm trying to roll my own DCT-II code to pass in an array of floats, each representing the log power of a mel frequency spectrum. I was expecting to get back positive amplitude values, but I am also getting ba... Raeldor

Voice Recognition over Bluetooth 5 34 (8/28/2011 5:35:19 AM) comp.dsp Hi All, I was wondering how voice recognition systems that work over bluetooth cope with the potentially huge difference in the spectogram produced from the source or training samples versus that of a (let's f... Raeldor

FFT and Sine Waves Question 35 64 (8/26/2011 5:18:59 AM) comp.dsp Hi All, I was doing some experimenting and was wondering if someone could explain my results. I have a pure sine wave at 1000hz generated into a wave file. I also have some FFT code to produce a spectrograph... Raeldor

The Theory Behind Why DCT is Used for MFCC Feature Vectors? 7 31 (3/14/2011 5:07:10 AM) comp.dsp Hi All, Does anyone have a good link to the theory behind why DCT is used for MFCC feature vectors? What exactly is it about the DCT values of the mel frequency spectrum that makes it so appealing for voice r... Raeldor

Formula to Find Resonant Frequencies? 10 23 (3/12/2011 11:01:43 PM) comp.dsp Hi All, Is there a formula or mathematical concept to find the resonant frequencies in a sound wave? Thanks Rael ... Raeldor

Auto-Covariance help 7 29 (3/8/2011 12:42:16 AM) comp.dsp Hi All, I'm trying to calculate the auto co-variance of a 16khz audio signal. The signal has been normalized between -1.0 and 1.0. I am using the following explanation of co-variance to calculate the auto-cov... Raeldor

Voice Recognition Sample Rate vs Mel Channels 1 142 (2/26/2011 4:36:49 PM) comp.dsp Hi All, I was sampling at 8000hz, and was using triangular overlapping windows to produce 20 mel channel values. If I increase my sample rate to 16000hz, should I also increase my mel channels to 40 as no... Raeldor

MFCC Code Sanity Check 0 128 (1/27/2011 5:58:25 AM) comp.dsp Hi All, I have been reading up on MFCC's and written some code based on what I've been reading. The results kind of make sense, but it's a little hard to tell. Does anyone here know this stuff well enoug... Raeldor

How do I Calculate Log Energy? 8 205 (12/17/2010 5:07:03 AM) comp.dsp Hi, Can someone tell me how to calculate log energy as shown in #7 in the following document? I thought it was just a total of the log of each of the 20 log energy values, but this seems to come out the s... Raeldor

raeldor's replies:

Items(7) /1

FFT Questions 14 266 (7/25/2010 4:57:45 AM) comp.dsp Hi Guys, I want to use FFT for an audio programming project I'm working on and had some (what are probably quite simple questions). I understand the concept that FFT converts a time based array of data in... raeldor (34)

Auto-Covariance help 7 29 (3/8/2011 12:42:16 AM) comp.dsp Hi All, I'm trying to calculate the auto co-variance of a 16khz audio signal. The signal has been normalized between -1.0 and 1.0. I am using the following explanation of co-variance to calculate the auto-cov... raeldor (34)

Formula to Find Resonant Frequencies? 10 23 (3/12/2011 11:01:43 PM) comp.dsp Hi All, Is there a formula or mathematical concept to find the resonant frequencies in a sound wave? Thanks Rael ... raeldor (34)

The Theory Behind Why DCT is Used for MFCC Feature Vectors? 7 31 (3/14/2011 5:07:10 AM) comp.dsp Hi All, Does anyone have a good link to the theory behind why DCT is used for MFCC feature vectors? What exactly is it about the DCT values of the mel frequency spectrum that makes it so appealing for voice r... raeldor (34)

FFT and Sine Waves Question 35 64 (8/26/2011 5:18:59 AM) comp.dsp Hi All, I was doing some experimenting and was wondering if someone could explain my results. I have a pure sine wave at 1000hz generated into a wave file. I also have some FFT code to produce a spectrograph... raeldor (34)

Voice Recognition over Bluetooth 5 34 (8/28/2011 5:35:19 AM) comp.dsp Hi All, I was wondering how voice recognition systems that work over bluetooth cope with the potentially huge difference in the spectogram produced from the source or training samples versus that of a (let's f... raeldor (34)

FFT vs DCT 36 30 (9/26/2011 2:29:15 PM) comp.dsp Hi All, I'm trying to understand the differences between FFT and DCT and was hoping someone may be able to help me with a couple of questions. 1. Is DCT basically the same as an FFT that operates on real numb... raeldor (34)