#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.
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