HDTenEightyP/NetNews huggingface dataset:
From: croteau@ccwf.cc.utexas.edu (Ed Croteau)
Newsgroups: comp.dsp
Subject: Numerical Recipes FFT routine bugs ???
Date: 24 Jul 92 19:26:34 GMT
Reply-To: croteau@ccwf.cc.utexas.edu (Ed Croteau)
Organization: The University of Texas at Austin, Austin TX
Originator: croteau@doc.cc.utexas.edu

Does anyone have any information on the "FOUR1.C" routine in the
Numerical Recipes in C book? I believe that the routine as printed
(and on a source disk) does not properly compute the FFT (try a 
simple real SIN wave and examine the imaginary).  Please let me know
if I am wrong about this but it seems like the imaginary part is
frequency reversed or something similar.  Please respond via email
if you have information or would like to hear of the results of this
posting.  Thanks.

P.S. How can I get in touch with the company? Their Cambridge address
is no longer valid (or at least no phone listing).


Newsgroups: comp.dsp
From: Donald.Kennedy@bbs.oit.unc.edu (Donald Kennedy)
Subject: IRIS Indigo audio
Keywords: 56001, Indigo, SGI, digital audio
Organization: Extended Bulletin Board Service
Date: Thu, 30 Jul 1992 23:57:15 GMT

I have read recently that SGI has chosen not to provide direct programming
support for the onboard 56001 on its Indigo computer. Does anyone know
what kind of audio DSP support SGI is planning for the Indigo other than
digital audio recording/playback (including multiple channel I/O)?


--
   The opinions expressed are not necessarily those of the University of
     North Carolina at Chapel Hill, the Campus Office for Information
        Technology, or the Experimental Bulletin Board Service.
           internet:  bbs.oit.unc.edu or 152.2.22.80
From: pdh@netcom.com (Phil Howard )
Newsgroups: comp.dsp
Subject: different windowing for continuous FFT
Date: 31 Jul 92 19:31:36 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

The only FAQ I can find under comp.dsp is for audio file formats.

I'm interested in a summary of different kinds of windowing that would be
usable with continuous Fourier transforms.  It would seem that this should
at least be in a general coverage technical FAQ for this group, but such
an FAQ has not yet been found.  So maybe if someone knows this stuff they
could start by posting some summary.

I've wondered if it is feasible to use (1-cos(x))/2 with x=0..2*pi as
a sampling window.  I'd like to know what the effects, advantages, and
disadvantages of different windows are, and how to interprete the data
gotten from with them.
-- 
/***********************************************************************\
| Phil Howard  ---  KA9WGN  ---  pdh@netcom.com   |   "The problem with |
| depending on government is that you cannot depend on it" - Tony Brown |
\***********************************************************************/
Newsgroups: comp.dsp
From: jxr1092@ritvax.isc.rit.edu (Jens Rodenberg)
Subject: Re: Adress of memory beyond 1M on PC
Reply-To: jxr1092@ritvax.isc.rit.edu
Organization: Rochester Institute of Technology
Date: Mon, 27 Jul 1992 01:12:02 GMT


Zhang Ya Xin writes:

>    We have a TANG IBM/PC 386 which has 4M of memory. Normally the adress
>of memory in the PC consists of a segment plus an offset, say, ****:****.
>1M is the limitation. My question is how can I access the memory beyond 1M?
>In other words, is there an adress of the memory beyond 1M in the PC?

   For my thesis (a prototype for a real-time image processing board), I
needed to access memory above 1M on a 386, for storing images above 1M and
also accessing the board's memory which is at 8M, just above the PC's
memory.  An MS-DOS function call (int 15H, AH = 87H) is all that's
needed for the memory transfer, which can transfer a buffer to extended
memory and vice-versa.  The source and destination addresses are specified
before the fuction call.  More details and example assembly code can be
found in an MS-DOS book, which I don't recall the name of (maybe it's just
"MS-DOS").  A memory transfer of up to 64K can be done, but Turbo C wouldn't
allow me to declare such a large array, so I had to go with 32K.

						Jens

P.S. To any potential employers: I would like to get a DSP job, as my thesis
     has given me experience with the design, simulation, and construction of
     an image processing board.  E-mail for more details if you're looking
     for a design engineer (BS in Electrical and Computer Engineering, almost
     MS in Computer Engineering).  Thanks.
From: gingell@aurs01.UUCP (Mike Gingell)
Newsgroups: comp.dsp
Subject: Re: Energy within a Digitized Pulse
Keywords: Attenuation, Energy, :-)
Date: 29 Jul 92 12:58:16 GMT
Reply-To: gingell@aurw6b.aur.alcatel.com.UUCP (Mike Gingell)
Organization: Alcatel Network Systems, Raleigh NC

There is of course NO energy in a DIGITIZED pulse since it is purely
numeric.  Energy is only meaningful if you translate it back to the
real world and assume a smooth curve drawn through the numbers,
representing a given voltage in a given impedance for a given amount
of time.

Am I a pedant or what? :-)

Mike Gingell, Alcatel, Raleigh, NC USA  (919) 850-6444
UUCP:       ...!mcnc!aurgate!aurfs1!gingell
Internet:   gingell%aurfs1%aurgate@mcnc.org
Newsgroups: comp.dsp
From: tsuanian@cc.curtin.edu.au
Subject: wavelets in speech recognition
Organization: Curtin University of Technology
Date: Wed, 29 Jul 1992 05:01:36 GMT

I am interested in applying wavelets to speech analysis.
Is anybody using wavelets for speech recogniton?

Any replys would be greatly appreciated.


Ian
-- 
 Internet: TSUANIAN@cc.curtin.edu.au
 Bitnet: TSUANIAN%cc.curtin.edu.au@cunyvm.bitnet
 UUCP  : uunet!munnari.oz!cc.curtin.edu.au!TSUANIAN
Newsgroups: comp.dsp
From: diaz@oakhill.sps.mot.com (Rafael Diaz)
Subject: Re: DSP C-source-code-book
Keywords: DSP, DSP-programs, C-source-codes
Organization: Motorola Inc., Austin Tx.
Date: Wed, 22 Jul 1992 16:51:12 GMT

In article <1992Jul22.075103.16462@dxcern.cern.ch> tchamov@sunran1.cern.ch (Nikolay Tchamov) writes:
>
>Does anyone knows about DSP-book with C-source-codes of subroutines ? 
>I think, somewhere was printed an article (1990 or 1991) about such book. 
>Have you seen it, what is the author-name, book-title exactly, 
>editoral-company and what are the estimations about it ?
>

	"C Language Algorithms for Digital Signal Processing"
	Authors: Paul M. Embree
		 Bruce Kimble

	Prentice Hall, 1991 Edition. 

	The book contain all C-source-codes listing & a DOS disk.


________________________________________________________________________
		       __        _    
  =_   __   ___    =  /  )      / )   ==========   diaz@sigi.sps.mot.com
 =  ) /_ )     )  =  /--<  _  -/-     == oakhill!sigi!diaz@cs.utexas.edu
=    ___/     /  =  /   / (_( /  (_/  ==========   Ph:  (512)   891 2977
=== Rafy Diaz ===== Motorola Inc. / DSP Operations, Austin TX ==========
			         /
-- 
________________________________________________________________________
		       __        _    
  =_   __   ___    =  /  )      / )   ==========   diaz@sigi.sps.mot.com
 =  ) /_ )     )  =  /--<  _  -/-     == oakhill!sigi!diaz@cs.utexas.edu
From: dpkemp@afterlife.ncsc.mil (David P. Kemp)
Newsgroups: comp.dsp
Subject: Re: Energy within a Digitized Pulse
Keywords: Attenuation, Energy, :-)
Date: 31 Jul 92 00:20:43 GMT
Organization: The Great Beyond

In article <dak.712512304@tabaqui> dak@tabaqui.informatik.rwth-aachen.de (David Kastrup) writes:
>Usually you interpret the digital values as Dirac pulses with the appropriate
>amplitude. The energy of a single such pulse is infinite. However,
>the digitized pulses are lowpass-filtered before reproduction, thus achieving
>finite energy again. Without this filtering (even if obly in theory or
>conceptional) energy cannot be calculated.

Usually I interpret the digital values as impulse (delta) functions with the
appropriate *energy*.  Delta functions are defined by their integrals, such
that integrating over a single pulse gives a finite energy.  The amplitude
of an impulse is infinite, but it's duration is infinitesimal.


-- 
   Dave Kemp   dpkemp@afterlife.ncsc.mil 
-----------------------------------------------------------------------------
"The use of history as therapy means the corruption of history as history."
    -- Arthur Schlesinger          (quote stolen from Chet Ramey, CWRU)
Newsgroups: comp.dsp
From: singer@maestoso.mit.edu (Andrew C Singer)
Subject:  Help on Tools for DSP Development
Organization: Digital Signal Processing Group, M.I.T. Research Lab for
	Electronics
Date: Thu, 30 Jul 1992 16:25:23 GMT


I am looking for help in collecting information about a wide range of
DSP development tools, both commercial and academic.  Particularly, I
am interested in tools that speed the process of turning signal
processing ideas into real systems.  By real system I mean dedicated
hardware, such as a modem, not DSP cards for PCs.  I can think
immediately of the following classes of tools:

1. Tools for algorithm development.  These tools allow the algorithm
designer to rapidly test alternative algorithms and to verify their
performance on real data sets.  The examples that jump to my mind are
MATLAB and Nth Power.  The issues in these types of tools is how fast
they allow you to try out ideas, how much support do they have for
generation of synthetic data sets, how easily can you analyze your
algorithms, etc.

2. Tools for signal processing software development.  These tools
allow you to specify your algorithm in "high level" signal processing
language from which runtime code can be automatically generated.  I do
not mean C compilers for DSP chips.

3. Tools for signal processing hardware development.  Similar to
software generation tools.  These tools allow high level
specifications to be turned into hardware descriptions.  An example of
such a tool is DSP Station from MENTOR.  It can generate hardware
descriptions for a set of signal processing operations.

I am especially interested in integrated tool sets, i.e., tools that
do some combination of the above three tasks in an integrated
framework.

I would appreciate any type of response:

        * Here is the name of a vendor or a professor to contact

        * I've used XYZ and it is great for ABC and poor for DEF

        * Here is another whole class of tools you have missed

Since this is so open-ended please respond directly via email rather than
flooding comp.dsp.

Thanks.
From: dak@tabaqui.informatik.rwth-aachen.de (David Kastrup)
Subject: Re: Energy within a Digitized Pulse
Keywords: Attenuation, Energy, :-)
Organization: Rechnerbetrieb Informatik  /  RWTH Aachen
Date: 30 Jul 92 16:05:04 GMT

gingell@aurs01.UUCP (Mike Gingell) writes:

>There is of course NO energy in a DIGITIZED pulse since it is purely
>numeric.  Energy is only meaningful if you translate it back to the
>real world and assume a smooth curve drawn through the numbers,
>representing a given voltage in a given impedance for a given amount
>of time.

>Am I a pedant or what? :-)

>Mike Gingell, Alcatel, Raleigh, NC USA  (919) 850-6444
>UUCP:       ...!mcnc!aurgate!aurfs1!gingell
>Internet:   gingell%aurfs1%aurgate@mcnc.org
Usually you interpret the digital values as Dirac pulses with the appropriate
amplitude. The energy of a single such pulse is infinite. However,
the digitized pulses are lowpass-filtered before reproduction, thus achieving
finite energy again. Without this filtering (even if obly in theory or
conceptional) energy cannot be calculated.
Newsgroups: comp.dsp
From: nyarko@ee.ualberta.ca (David Nyarko)
Subject: Actual FFT components after windowing
Organization: University Of Alberta, Edmonton Canada
Distribution: na
Date: Fri, 31 Jul 1992 13:24:56 GMT

Hi,
Could anyone help me with the actual scale
factors required to obtain the correct
harmonic components(Amplitudes) for the components
obtained by using a DFT/FFT and:
a) Hanning Window
b) Hamming Window

The input sequence values are multiplied by the
window coefficients before performing the DFT/FFT
on the new sequence values.

email address: nyarko@bode.ee.ualberta.ca
From: liuc@madrone.eecs.ucdavis.edu (Chia-Liang Liu)
Newsgroups: comp.dsp
Subject: Re: Energy within a Digitized Pulse
Keywords: Attenuation, Energy
Date: 24 Jul 92 03:00:42 GMT
Organization: U.C. Davis - Department of Electrical and Computer Engineering

In article <BruE1t.A8L@watserv1.waterloo.edu> jssloka@ritchie.waterloo.edu (Jeffery Scott Sloka) writes:
>Howdy.  I have two questions which I can't seem to nail down properly and
>I'm humbly asking for your expertise.

>1.  The energy of a continuous time signal is just the integral of
>the square of the signal.  For a digitized signal, is it true that
>the energy contained is just the sum of the squares of each point?

Yes, if you assume that the sampling interval, Ts, is 1.0; otherwise
you need to multiply it by Ts to get the energy.

>2.  The attenuation of a signal is related to the amount that the
>signal decreases.  If the signal maintains its shape, is the
>attenuation the ratio of the two energies or is it the square root
>of the ratio of the energies?

If your 'attenuation' is in linear scale, you need to specify it
is power (energy) or voltage (current). That's why in engineering,
engineers use 'dB' to specify 'attenuation'. If I say the attenuation
is 20 dB, it means voltage (current) is attenuated by 10 times, while
power (energy) is attenuated by 100 times.

>
>Sorry to ask such basic questions but I could not find a text to confirm any of these questions in the discrete time domain.  Many thanks in advance for your replies.
>
>	-Scott


-- 
Ka-Leung Lau ( Chia-Liang Liu )
Digital Communications Research Laboratory
Department of Electrical and Computer Engineering 
University of California, Davis (Cal Aggies)
From: liuc@madrone.eecs.ucdavis.edu (Chia-Liang Liu                                                                   Ka -Leung Lau)
Newsgroups: comp.dsp
Subject: Re: Energy within a Digitized Pulse
Keywords: Attenuation, Energy
Date: 29 Jul 92 03:43:27 GMT
Organization: U.C. Davis - Department of Electrical and Computer Engineering

In article <TeNmoB1w164w@gmp.lonestar.org> greg@gmp.lonestar.org (G.R. Basile) writes:
>
>I agree. What has piqued my curiousity is how to derive an exact solution
>of the power of the continuous time signal from the sampled data. What about
>taking an fft of the samples and than summing the square of the magnitudes ? 
>What errors are introduced?
>
>Greg Basile
>greg@gmp.lonestar.org
>

The information provided by a digitized signal and its FFT is
identical. Since you can not calculate the energy of a signal from
its samples EXACTLY, you can't calculate it from its FFT either. If
you are not satisfied with the approximation, the best way is to LPF
the digitized signal and measure the analog power assuming you
sample the signal above the Nyquist rate and the filter doesn't cause
distortion, attenuation, ..... etc.

-- 
Ka-Leung Lau ( Chia-Liang Liu )
Digital Communications Research Laboratory
Department of Electrical and Computer Engineering 
University of California, Davis (Cal Aggies)
From: cpyy@vax5.cit.cornell.edu
Newsgroups: comp.dsp
Subject: Re: Numerical Recipes FFT routine bugs ???
Date: 28 Jul 92 09:32:32 EDT
Distribution: comp
Organization: Cornell University

In article <$=c1Hsr*p8@atlantis.psu.edu>,
mek@guinan.psu.edu (Mark E. Kotanchek) writes: 
> In article <1992Jul24.203717.2527@bert.eecs.uic.edu>  
> eddins@bert.eecs.uic.edu (Dr. Steven L. Eddins) writes:
>> croteau@ccwf.cc.utexas.edu (Ed Croteau) writes:
>> 
>> >Does anyone have any information on the "FOUR1.C" routine in the
>> >Numerical Recipes in C book? I believe that the routine as printed
>> >(and on a source disk) does not properly compute the FFT (try a 
>> >simple real SIN wave and examine the imaginary).  Please let me know
>> >if I am wrong about this but it seems like the imaginary part is
>> >frequency reversed or something similar.

I also tried to implement the Numerical Recepie's algorithm for
speech processing algorithms.  Strangely, if you do a forward
transform followed by a reverse transform, you don't get back
your original input.  I had to go through the Cooley-Tukey
derivation to produce the correct algorithm.  It seems that
the one in the book is bass-ackwards in such a way that it will
produce a meaningful magnitude result, with a quasi-meaningless
reversed phase result.

-- 

Jon C. Russo
internet : cpyy@vax5.cit.cornell.edu
phone    : 607.277.3295
Newsgroups: comp.dsp,sci.math,sci.math.num-analysis
From: gill@physics.ubc.ca (Arnold Gill)
Subject: Re: Help: Battle-Lemarie Wavelets
Organization: University of British Columbia, Vancouver, B.C., Canada
Date: Sat, 25 Jul 1992 18:52:54 GMT

pappu@vu-vlsi.vill.edu (Strange Attractor) writes:

>I have been trying to generate the Battle-Lemarie wavelet and scaling functions
>I have had some problems in implementing the algorithm given in Mallat's
>paper in that I do not get enough points in the basic scaling function
>phi(0,0).  When I dilate this function, I am not able to evaluate the dilated 
>function wherever I like because of the lack of points. 

     I think this may be a generic problem whenever you use a discrete wavelet
     rather than a continuous one.  Eventually, your wavelet becomes too big 
     for the data and there just aren't enough points left.  If you have a
     continuous function describing the wavelet, you can always add in the 
     missing pieces.

     By the way, don't you just use the same number of coefficients, but
     sample the data stream at larger intervals when dilating the wavelet?

--
Arnold Gill --- astrophysician trainee in exile             gill@physics.ubc.ca
From: 8918927y@levels.unisa.edu.au
Newsgroups: comp.dsp
Subject: WANTED: Info on Motorola DSP56401 chip.
Date: 30 Jul 92 01:49:28 GMT
Organization: University of South Australia


Hello,
	Could somebody please tell me where I can obtain information
about a new chip from Motorola. It was mentioned in a recent issue of
EDN. It's number is DSP56401 and it's a interface between a DSP56001 dsp
and the AES/EBU digital audio interface. I have asked my local Motorola
distributor in Australia, but they don't know the device.

Thanks for your help.
Kym
------------------------------------------------------------------------------
 Kym B Newbery : 8918927y@lux.levels.UniSA.edu.au : 4th Year electronic eng.
Newsgroups: comp.dsp
From: jim@fuji.eng.yale.edu (James J. Szinger)
Subject: Re: Energy within a Digitized Pulse
Organization: Yale Univerity, Intelligent Sensors Lab, Elect. Eng.
	<15598@ucdavis.ucdavis.edu>
Date: 29 Jul 92 10:35:19

In article <15598@ucdavis.ucdavis.edu>
liuc@madrone.eecs.ucdavis.edu (Chia-Liang Liu Ka -Leung Lau)
writes:
>In article <TeNmoB1w164w@gmp.lonestar.org> greg@gmp.lonestar.org (G.R. Basile) writes:
>>
>>I agree. What has piqued my curiousity is how to derive an exact solution
>>of the power of the continuous time signal from the sampled data.

>The information provided by a digitized signal and its FFT is
>identical. Since you can not calculate the energy of a signal from
>its samples EXACTLY, you can't calculate it from its FFT either.

To me it is conceptually easy to obtain the EXACT power from the
samples.  Start by discretizing x(t) to get x[i].  By sampling at
more than four times the highest frequency in x(t), the sampling
criteria are satisfied for x^2(t).  The power in x(t) is the
integral from minus to plus infinity of x^2(t).  But x^2(t) is
equal to the sum of sinc functions weighted by x^2[i].  The
integral of the sinc function can be found in a table of
integrals, so the power simplifies to a weighted sum of x^2[i].
It is left as an exercise for the reader to carefully derive the
correct weights, but the principle is straight forward and it
clearly can be done.

Jim
--
James Szinger                        jim@fuji.eng.yale.edu
Newsgroups: comp.dsp
From: mek@guinan.psu.edu (Mark E. Kotanchek)
Subject: Re: Numerical Recipes FFT routine bugs ???
Organization: Penn State Center for Academic Computing
Date: Sun, 26 Jul 92 18:35:36 GMT

In article <1992Jul24.203717.2527@bert.eecs.uic.edu>  
eddins@bert.eecs.uic.edu (Dr. Steven L. Eddins) writes:
> croteau@ccwf.cc.utexas.edu (Ed Croteau) writes:
> 
> >Does anyone have any information on the "FOUR1.C" routine in the
> >Numerical Recipes in C book? I believe that the routine as printed
> >(and on a source disk) does not properly compute the FFT (try a 
> >simple real SIN wave and examine the imaginary).  Please let me know
> >if I am wrong about this but it seems like the imaginary part is
> >frequency reversed or something similar.
> 
> Perhaps your difficulty is in their definition of the DFT (Discrete
> Fourier Transform).  See equations (12.1.7) and (12.1.9), and note
> that the signs in the complex exponential terms are reversed from the
> engineering norm.  Or maybe I shouldn't say "norm"---it's reversed
> from the definition *I* use.  ;-)

Bingo! The problem is that mathematicians view the Fourier transform as a  
transform pair and "a tranform is a transform is a transform" while us  
engineers have this perverted idea that a physical meaning should be  
attached to the domain representations.

Anyhow, to solve the problem, simply use the inverse FFT whenever you want  
an FFT and vice versa. Unfortunately, Numerical Recipes is not an isolated  
case of this potentially dangerous definition of the FFT--the Extend  
simulation language on the Mac uses the mathematician's definition and (I  
think) MathCAD also is "in error".

--
Mark Kotanchek
Guidance & Control Dept - 363 ASB
Applied Research Lab/Penn State
P.O. Box 30
State College, PA 16804

Newsgroups: comp.dsp
From: jssloka@ritchie.waterloo.edu (Jeffery Scott Sloka)
Subject: Energy within a Digitized Pulse 
Keywords: Attenuation, Energy 
Organization: University of Waterloo
Date: Thu, 23 Jul 1992 12:44:16 GMT

Howdy.  I have two questions which I can't seem to nail down properly and I'm humbly asking for your expertise.

1.  The energy of a continuous time signal is just the integral of the square of the signal.  For a digitized signal, is it true that the energy contained is just the sum of the squares of each point?

2.  The attenuation of a signal is related to the amount that the signal decreases.  If the signal maintains its shape, is the attenuation the ratio of the two energies or is it the square root of the ratio of the energies?

Sorry to ask such basic questions but I could not find a text to confirm any of these questions in the discrete time domain.  Many thanks in advance for your replies.

	-Scott
From: bill@allegra.att.com (Bill Schell)
Newsgroups: comp.soft-sys.andrew
Subject: Re: Compressed messages?
Date: 23 Jul 92 15:59:11 GMT
Distribution: world
Organization: The Internet

While you're at it, it would be easy to add encryption in the same way. 
On opening a folder with a particular extension (like .x for encrypted),
 messages would put up a dialog box and prompt the user for a key to use
when decrypting the messages in that folder.   There are some fairly
fast publicly available implementations of DES around to the the
encrypt/decrypt part.  Todd, I could
send you one of these if you're interested in pursuing this.

Bill Schell
AT&T Bell Labs, Murray Hill, NJ
bill@allegra.att.com