#features
   -realtime (50fps) analyzer displays:
      -oscilloscope + spectrum analyzer
      -spectrogram (a.k.a. 'waterfall plot')
   -full source code included


 #requirements
   -AGA chipset
   -CPU 68020+
   -FPU 68881/2 or 68040/060
   -sound sampler (8bit, parallel port)
   -15kHz-capable monitor (for PAL video output)

   -tested configurations:
      -A1200, 68030+882 @ 40MHz, 16MB (yes, this is fast enough!)
      -A1200, 68060 @ 50MHz, 48MB (works well...)




;
;
;---------------------------------
;
; scope_xt4
; code by Smack/Infect!
; Sat 01-May-99
;
;---------------------------------
;
;


 #what's this program good for?
   scope_xt4 is some kind of tech-toy. I like to run it on my good old
   A1200 when I listen to music, just for the visual effect.


 #how to use it
   plug in your sound sampler, turn on the music and launch the program.

   some keyboard functions are also displayed on the status panel:
   -F1-   screen 1: oscilloscope + spectrum analyzer
   -F2-   screen 2: spectrogram
   -Q-    FFT window function: rectangle
   -W-    FFT window function: Hamming
   -E-    FFT window function: Hanning
   -R-    FFT window function: triangle
   -T-    FFT window function: Blackman
   -1-    frequency range: 12 kHz
   -2-    frequency range:  6 kHz
   -3-    frequency range:  3 kHz
   -A-    intensity scale: logarithmic
   -S-    intensity scale: linear
   -8-    audio output: on
   -9-    audio output: off

   and then there are some more keyboard functions:
   -Del-  test mode (built-in synthetic samples)
   -F4-   oscilloscope on/off
   -F5-   spectrum analyzer on/off
   -F9-   show CPU idle
   -F10-  freeze display
   -Esc-  quit


 #the analyzer displays
   -oscilloscope (time-amplitude plot)
             horizontal: time (range 20ms, resolution 40µs)
               vertical: amplitude (-128...+127)

   -spectrum analyzer (frequency-intensity plot)
             horizontal: frequency (range -1-, -2- or -3-)
               vertical: intensity (0...127)
       
   -spectrogram (frequency-time-intensity plot)
             horizontal: frequency (range -1-, -2- or -3-)
               vertical: time (range 4.8s, resolution 20ms)
             brightness: intensity (0...255)


 #a few technical details
   -sampling and playback are performed at a rate of about 25200Hz
    by using a level4 hardware interrupt (no cia timers used).
   -the spectrum analyzer provides 250 frequency channels. compare that
    to the usual hifi equipment - there you can get analyzers with seven
    channels, sometimes even more - wow!
   -the code is optimized for 68030 machines (because I've got one), it
    will still perform very well on faster CPUs (68040 or 68060).
   -recently I figured out how the intensity scaling of the FFT routine
    can be done faster and more accurate using the FPU.


 #acknowledgement
   the ultra fast 504-point FFT routine was taken from:
       ---------------------------------------------------------
         DeliTracker FFTAnalyzer genie module V1.6 (19 Apr 95)

             © 1994-95 by Delirium Softdesign
             (Peter Kunath and Frank Riffel)
                 All rights reserved.
             Special thanks to Kim Øyhus for
            the fastest FFT routine ever done
                     on the Amiga.
       ---------------------------------------------------------


 #author
   email: smack@smack.de

   scope_xt4 is Copyright (c) 1998/1999 by Michael Henke.
   It is released as FREEWARE, which means it may be distributed and used
   for free, but no profit may be made with it (neither by selling the
   program nor by using it for commercial purposes). The program and the
   information within this text are provided 'AS-IS'. The entire risk as
   to its quality and performance is with the user. In no event will the
   author be liable for direct, indirect, incidental or consequential
   damages resulting from any defect in the program.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                13564   45968  29.5% -lh5- 65e4 May  1  1999 scope_xt4/scope_xt4
[generic]                 1811    4039  44.8% -lh5- 4bc4 May  1  1999 scope_xt4/scope_xt4.readme
[generic]                 1769    6352  27.8% -lh5- 9f38 May  1  1999 scope_xt4/src/bin/function_panel.iff
[generic]                  952    3872  24.6% -lh5- 71e0 May  1  1999 scope_xt4/src/bin/function_panel.sprite
[generic]                 1999   13256  15.1% -lh5- a822 May  1  1999 scope_xt4/src/bin/spectrum_screen.iff
[generic]                  775   12384   6.3% -lh5- 0a5a May  1  1999 scope_xt4/src/bin/spectrum_screen_full.raw
[generic]                  452    2112  21.4% -lh5- 4968 May  1  1999 scope_xt4/src/bin/spectrum_screen_topbottom.raw
[generic]                  211    2592   8.1% -lh5- 82ac May  1  1999 scope_xt4/src/bin/wave_screen.iff
[generic]                  112    8256   1.4% -lh5- 464c May  1  1999 scope_xt4/src/bin/wave_screen.raw
[generic]                  933    1008  92.6% -lh5- e223 May  1  1999 scope_xt4/src/bin/window_blackman.bin
[generic]                  923    1008  91.6% -lh5- 13df May  1  1999 scope_xt4/src/bin/window_hamming.bin
[generic]                  928    1008  92.1% -lh5- 6a6e May  1  1999 scope_xt4/src/bin/window_hanning.bin
[generic]                 7160   38308  18.7% -lh5- a4b4 May  1  1999 scope_xt4/src/deli_fft.i
[generic]                  269     701  38.4% -lh5- 8e05 May  1  1999 scope_xt4/src/dummysprites.i
[generic]                 7111   15690  45.3% -lh5- 4d59 May  1  1999 scope_xt4/src/fft_window_functions.iff
[generic]                  943    2529  37.3% -lh5- f395 May  1  1999 scope_xt4/src/hardware-registers.i
[generic]                 4983   14653  34.0% -lh5- 2aad May  1  1999 scope_xt4/src/os_macros.i
[generic]                  499    1735  28.8% -lh5- 6efa May  1  1999 scope_xt4/src/precalc_fft_windows.s
[generic]                 5850   24346  24.0% -lh5- 1a15 May  1  1999 scope_xt4/src/scope_xt4.s
[generic]                  562    1449  38.8% -lh5- d32c May  1  1999 scope_xt4/src/startup_nocheck.i
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        20 files   51806  201266  25.7%            May  4  1999