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Contents


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 LTFAT - Signals

  Signal generators
    CTESTFUN       -  Complex valued test function.
    NOISE          -  Stochastic noise generator.
    PINKNOISE      -  Pink noise.
    EXPCHIRP       -  Exponential chirp.

  Sound signals.
    BAT            -  Bat chirp.
    BATMASK        -  Mask for bat signal.
    GREASY         -  Woman speaking the word 'greasy'
    COCKTAILPARTY  -  Sentence by male, native English speaker.
    GSPI           -  Glockenspiel test signal.
    LINUS          -  Linus pronouncing Linux.
    LTFATLOGO      -  Synthetic sound from spectrogram reconstruction.
    OTOCLICK       -  Click-evoked otoacoustic emmision. 
    TRAINDOPPLER   -  Sound of passing train.

  Images.
    CAMERAMAN      -  Greyscale image of the cameraman.
    LICHTENSTEIN   -  Color image of the Lichtenstein castle.
    LTFATTEXT      -  Black and white word: 'LTFAT'.
    LTFATLOGO      -  LTFAT Logo.

  For help, bug reports, suggestions etc. please visit 
  http://github.com/ltfat/ltfat/issues


   Url: http://ltfat.github.io/doc/signals/Contents.html



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 LTFAT - Signals



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bat


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 -- Function: bat
     BAT  Load the 'bat' test signal
        Usage:  s=bat;
     
        BAT loads the 'bat' signal. It is a 400 samples long recording
        of a bat chirp sampled with a sampling period of 7 microseconds.
        This gives a sampling rate of 143 kHz.
     
        [sig,fs]=BAT additionally returns the sampling frequency fs.
     
        The signal can be obtained from
        http://dsp.rice.edu/software/bat-echolocation-chirp
     
        Please acknowledge use of this data in publications as follows:
     
          The author wishes to thank Curtis Condon, Ken White, and Al Feng of
          the Beckman Institute of the University of Illinois for the bat data
          and for permission to use it in this paper.
     
        Examples:
        ---------
     
        Plot of 'bat' in the time-domain:
     
          plot((1:400)/143000,bat);
          xlabel('Time (seconds)');
          ylabel('Amplitude');
     
        Plot of 'bat' in the frequency-domain:
     
          plotfftreal(fftreal(bat),143000,90);
     
        Plot of 'bat' in the time-frequency-domain:
     
          sgram(bat,143000,90);
     
     *Url*: <http://ltfat.github.io/doc/signals/bat.html>

     See also: batmask.


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BAT  Load the 'bat' test signal
   Usage:  s=bat;



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batmask


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 -- Function: batmask
     BATMASK  Load a Gabor multiplier symbol for the 'bat' test signal
        Usage:  c=batmask;
     
        BATMASK loads a Gabor multiplier with a 0/1 symbol that masks out
        the main contents of the 'bat' signal. The symbol fits a Gabor
        multiplier with lattice given by a=10 and M=40.
     
        The mask was created manually using a image processing program. The
        mask is symmetric, such that the result will be real valued if the
        multiplier is applied to a real valued signal using a real valued
        window.
     
     *Url*: <http://ltfat.github.io/doc/signals/batmask.html>

     See also: bat.


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BATMASK  Load a Gabor multiplier symbol for the 'bat' test signal
   Usage:  ...



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cameraman


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 -- Function: cameraman
     CAMERAMAN  Load the 'cameraman' test image
        Usage: s=cameraman;
      
        CAMERAMAN loads a 256 x256 greyscale image of a cameraman.
      
        The returned matrix s consists of integers between 0 and 255,
        which have been converted to double precision.
      
        To display the image, use imagesc with a gray colormap:
      
          imagesc(cameraman); colormap(gray); axis('image');
      
        See ftp://nic.funet.fi/pub/graphics/misc/test-images/ or
        http://sipi.usc.edu/database/database.cgi?volume=misc.
     *Url*: <http://ltfat.github.io/doc/signals/cameraman.html>


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CAMERAMAN  Load the 'cameraman' test image
   Usage: s=cameraman;
 
   CAMERA...



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cocktailparty


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 -- Function: cocktailparty
     COCKTAILPARTY  Load the 'cocktailparty' test signal
        Usage:  s=cocktailparty;
     
        COCKTAILPARTY loads the 'cocktailparty' signal. It is a recording of a
        male native English speaker pronouncing the sentence "The cocktail party
        effect refers to the ability to focus on a single talker among a mixture
        of conversations in background noises".
     
        [sig,fs]=COCKTAILPARTY additionally returns the sampling frequency fs.
     
        The signal is 363200 samples long and recorded at 44.1 kHz in an
        anechoic environment.
     *Url*: <http://ltfat.github.io/doc/signals/cocktailparty.html>


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COCKTAILPARTY  Load the 'cocktailparty' test signal
   Usage:  s=cocktailparty;



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ctestfun


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 -- Function: ctestfun
     CTESTFUN  Complex 1-D test function
        Usage:  ftest=ctestfun(L);
     
        CTESTFUN(L) returns a test signal consisting of a superposition of a
        chirp and an indicator function.
     *Url*: <http://ltfat.github.io/doc/signals/ctestfun.html>


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CTESTFUN  Complex 1-D test function
   Usage:  ftest=ctestfun(L);



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expchirp


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 -- Function: expchirp
     EXPCHIRP  Exponential chirp
        Usage: outsig=expchirp(L,fstart,fend)
     
        EXPCHIRP(L,fstart,fend) computes an exponential chirp of length L*
        starting at frequency fstart and ending at frequency fend. The
        freqencies are assumed to be normalized to the Nyquist frequency.
     
        EXPCHIRP takes the following parameters at the end of the line of input
        arguments:
     
          'fs',fs    Use a sampling frequency of fs Hz. If this option is
                     specified, fstart and fend will be measured in Hz.
     
          'phi',phi  Starting phase of the chirp. Default value is 0.
     
          'fc',fc    Shift the chirp by fc in frequency. Default values is 0.
     
          'ramp',r   Apply fade-in and fade out ramps on the first and last r samples.
     
     *Url*: <http://ltfat.github.io/doc/signals/expchirp.html>

     See also: pchirp.


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EXPCHIRP  Exponential chirp
   Usage: outsig=expchirp(L,fstart,fend)



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greasy


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 -- Function: greasy
     GREASY  Load the 'greasy' test signal
        Usage:  s=greasy;
     
        GREASY loads the 'greasy' signal. It is a recording of a woman
        pronouncing the word "greasy".
     
        The signal is 5880 samples long and recorded at 16 kHz with around 11
        bits of effective quantization.
     
        [sig,fs]=GREASY additionally returns the sampling frequency fs.
     
        The signal has been scaled to not produce any clipping when
        played. To get integer values use round(GREASY*2048).
     
        The signal was obtained from Wavelab:
        http://www-stat.stanford.edu/~wavelab/, it is a part of the first
        sentence of the TIMIT speech corpus "She had your dark suit in greasy
        wash water all year":
        http://www.ldc.upenn.edu/Catalog/CatalogEntry.jsp?catalogId=LDC93S1.
     
        Examples:
        ---------
     
        Plot of 'greasy' in the time-domain:
     
          plot((1:5880)/16000,greasy);
          xlabel('Time (seconds)');
          ylabel('Amplitude');
     
        Plot of 'greasy' in the frequency-domain:
     
          plotfftreal(fftreal(greasy),16000,90);
     
        Plot of 'greasy' in the time-frequency-domain:
     
          sgram(greasy,16000,90);
     
        References:
          S. Mallat and Z. Zhang. Matching pursuits with time-frequency
          dictionaries. IEEE Trans. Signal Process., 41(12):3397--3415, 1993.
          
     *Url*: <http://ltfat.github.io/doc/signals/greasy.html>


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GREASY  Load the 'greasy' test signal
   Usage:  s=greasy;



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gspi


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 -- Function: gspi
     GSPI  Load the 'glockenspiel' test signal
     
        GSPI loads the 'glockenspiel' signal. This is a recording of a simple
        tune played on a glockenspiel. It is 262144 samples long, mono, recorded
        at 44100 Hz using 16 bit quantization.
        
        [sig,fs]=GSPI additionally returns the sampling frequency fs.
     
        This signal, and other similar audio tests signals, can be found on
        the EBU SQAM test signal CD http://tech.ebu.ch/publications/sqamcd.
     
     *Url*: <http://ltfat.github.io/doc/signals/gspi.html>


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GSPI  Load the 'glockenspiel' test signal



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lichtenstein


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 -- Function: lichtenstein
     LICHTENSTEIN  Load the 'lichtenstein' test image
        Usage: s=lichtenstein;
      
        LICHTENSTEIN loads a 512 x512 color image of a castle
        Lichtenstein.
      
        The returned matrix s consists of integers between 0 and 255.
      
        To display the image, simply use image:
      
          image(lichtenstein); axis('image');
      
     *Url*: <http://ltfat.github.io/doc/signals/lichtenstein.html>

     See also: cameraman.


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LICHTENSTEIN  Load the 'lichtenstein' test image
   Usage: s=lichtenstein;
 
...



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linus


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 -- Function: linus
     LINUS  Load the 'linus' test signal
        Usage:  s=linus;
     
        LINUS loads the 'linus' signal. It is a recording of Linus Thorvalds
        pronouncing the words "Hello. My name is Linus Thorvalds, and I
        pronounce Linux as Linux".
     
        The signal is 41461 samples long and is sampled at 8 kHz.
     
        [sig,fs]=LINUS additionally returns the sampling frequency fs.
     
        See http://www.paul.sladen.org/pronunciation/.
     *Url*: <http://ltfat.github.io/doc/signals/linus.html>


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LINUS  Load the 'linus' test signal
   Usage:  s=linus;



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ltfatlogo


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 -- Function: ltfatlogo
     LTFATLOGO  Load the 'ltfatlogo' test signal
        Usage:  s=ltfatlogo;
     
        LTFATLOGO loads the 'ltfatlogo' signal. This is a sound synthezised
        from an artificial spectrogram of the word 'LTFAT'. See the help of
        LTFATTEXT.
     
        [sig,fs]=LTFATLOGO additionally returns the sampling frequency fs.
     
        The signal is 7200 samples long and recorded at 8 kHz. It has been
        scaled to not produce any clipping.
     
        Examples:
        ---------
     
        To produce a spectrogram of the logo, use:
     
          sgram(ltfatlogo,8000,90);
     
     *Url*: <http://ltfat.github.io/doc/signals/ltfatlogo.html>

     See also: ltfattext.


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LTFATLOGO  Load the 'ltfatlogo' test signal
   Usage:  s=ltfatlogo;



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ltfattext


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 -- Function: ltfattext
     LTFATTEXT  Load the 'ltfattext' test image
        Usage: s=ltfattext;
      
        LTFATTEXT loads a 401 x600 black and white image of the word
        'LTFAT'.
      
        The image is assumed to be used as a spectrogram with 800 channels
        as produced by DGTREAL.
      
        The returned matrix s consists of the integers 0 and 1, which have
        been converted to double precision.
      
        To display the image, use imagesc with a gray colormap:
      
          imagesc(ltfattext);
          colormap(gray);
          axis('xy');
      
     *Url*: <http://ltfat.github.io/doc/signals/ltfattext.html>

     See also: ltfatlogo, dgtreal.


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LTFATTEXT  Load the 'ltfattext' test image
   Usage: s=ltfattext;
 
   LTFATT...



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noise


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 -- Function: noise
      NOISE  Stochastic noise generator
        Usage: outsig = noise(siglen,nsigs,type);
     
        Input parameters:
            siglen    : Length of the noise (samples)
            nsigs     : Number of signals (default is 1)
            type      : type of noise. See below.
     
        Output parameters:
            outsig    : siglen xnsigs signal vector
     
        NOISE(siglen,nsigs) generates nsigs channels containing white noise
        of the given type with the length of siglen. The signals are arranged as
        columns in the output. If only siglen is given, a column vector is
        returned.
     
        NOISE takes the following optional parameters:
     
          'white'  Generate white (gaussian) noise. This is the default.
     
          'pink'   Generate pink noise.
     
          'brown'  Generate brown noise.
     
          'red'    This is the same as brown noise.     
     
        By default, the noise is normalized to have a unit energy, but this can
        be changed by passing a flag to SETNORM.
     
        Examples:
        ---------
         
        White noise in the time-frequency domain:
     
          sgram(noise(5000,'white'),'dynrange',70);
     
        Pink noise in the time-frequency domain:
     
          sgram(noise(5000,'pink'),'dynrange',70);
     
        Brown/red noise in the time-frequency domain:
     
          sgram(noise(5000,'brown'),'dynrange',70);
      
     *Url*: <http://ltfat.github.io/doc/signals/noise.html>

     See also: setnorm.


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 NOISE  Stochastic noise generator
   Usage: outsig = noise(siglen,nsigs,type);



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otoclick


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 -- Function: otoclick
     OTOCLICK  Load the 'otoclick' test signal
        Usage:  s=otoclick;
     
        OTOCLICK loads the 'otoclick' signal. The signal is a click-evoked
        otoacoustic emission. It consists of two clear clicks followed by a
        ringing. The ringing is the actual otoacoustic emission.
     
        [sig,fs]=OTOCLICK additionally returns the sampling frequency fs.
     
        It was measured by Sarah Verhulst at CAHR (Centre of Applied Hearing
        Research) at Department of Eletrical Engineering, Technical University
        of Denmark
     
        The signal is 2210 samples long and sampled at 44.1 kHz.
     *Url*: <http://ltfat.github.io/doc/signals/otoclick.html>


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OTOCLICK  Load the 'otoclick' test signal
   Usage:  s=otoclick;



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pinknoise


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 -- Function: pinknoise
      PINKNOISE Generates a pink noise signal
        Usage: outsig = pinknoise(siglen,nsigs);
     
        Input parameters:
            siglen    : Length of the noise (samples)
            nsigs     : Number of signals (default is 1)
     
        Output parameters:
            outsig    : siglen xnsigs signal vector
     
        PINKNOISE(siglen,nsigs) generates nsigs channels containing pink noise
        (1/f spectrum) with the length of siglen. The signals are arranged as
        columns in the output.
     
        PINKNOISE is just a wrapper around noise(...,'pink');
     
     *Url*: <http://ltfat.github.io/doc/signals/pinknoise.html>

     See also: noise.


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 PINKNOISE Generates a pink noise signal
   Usage: outsig = pinknoise(siglen,...



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traindoppler


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 -- Function: traindoppler
     TRAINDOPPLER  Load the 'traindoppler' test signal
        Usage:  s=traindoppler;
     
        TRAINDOPPLER loads the 'traindoppler' signal. It is a recording
        of a train passing close by with a clearly audible doppler shift of
        the train whistle sound.
     
        [sig,fs]=TRAINDOPPLER additionally returns the sampling frequency
        fs.
     
        The signal is 157058 samples long and sampled at 8 kHz.
     
        The signal was obtained from
        http://www.fourmilab.ch/cship/doppler.html
     *Url*: <http://ltfat.github.io/doc/signals/traindoppler.html>


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TRAINDOPPLER  Load the 'traindoppler' test signal
   Usage:  s=traindoppler;





