Signal Generation tools for Linux and /dev/dsp                Jim Jackson
----------------------------------------------                  Feb  1998

Release 2.1

What are the programs?

This is a set of tools for imitating a laboratory Signal Generator,
generating audio signals out of Linux's /dev/dsp audio device. There is
support for mono and/or stereo and 8 or 16 bit samples. The basic waveform
sample generation code is in the file generator.c, the functions here can be
added to other programs fairly easily. 

Several of the programs below are front ends for using the generator
functions, mixing the generated outputs and playing them on /dev/dsp. None
of the generation programs control the mixer - use your favourite mixer
program or use the simple mixer 'smix' which I have included here.

soundinfo   A program to display some of the programming capabilities
            of the sound system support for the mixer device /dev/mixer
            and the DSP device /dev/dsp. Can easily be changed if
            the mixer and dsp devices are called something else. Also
            shows some of the ioctl calls in action :-).
            Further info on your kernel's sound card configuration is
            given by 'cat /dev/sndstat'.

sgen        is a command line signal generator where
            details are specified from the command line for generating
            sine, cos, square, triangle, sawtooth, pulse, noise waves.
            Frequency, sample rate, relative amplitude etc can be
            specified thru' command line options. The signal is played 
            continuously until the program is stopped. There are options
            to save the basic raw digital samples raw to file or to a WAVE
	    format file.

swgen       is a command line sweep generator. Both the sweeping and swept
            waveforms can be specified, along with the sweeping frequency
	    and the swept frequency range. Otherwise similar to sgen above.
	    
siggen      an Ncurses screen based Signal Generator for 2 seperate channels.
            On stereo audio cards the 2 channels are played on seperate 
            outputs. On mono cards the 2 channels are digitally
            mixed onto the one output. Type of waveform, frequency, amplitude,
            sample rate etc are specified/changed via a screen menu.
	    This is version 2. It plays continuously. Changes to parameters
	    take effect (nearly) immediately. This version is pretty CPU
	    intensive.
	    
sweepgen    an Ncurses screen based Sweep generator (see swgen above).
	    It is like siggen. Changes to parameters take effect  (nearly)
            immediately. 
 
tones       a command line program to generate several successive tones of
            varying freq., and optional differing waveforms and durations.
            The sequence of tones can be either played once (the default), 
            or repetitively or the samples can be written to a file in raw or 
            WAV format. This could make the basis of an auto-dialer for 
            tone phones.
            Check out README.tones and the tones.eg directory for some
            examples of using the tones program.

smix        a simple command line program for getting and setting the mixer
            settings. (Eee by gum, yet another mixer, yawn).
	    

Compiling and installing

You will need the ncurses library and header files. You will need sound card
support compiled into your kernel.

Check out the Makefile and edit anything that is wrong for your system. The
ncurses library is assumed to be in normal library 'path' and the
ncurses include file is assumed to be in either /usr/include/curses or
/usr/include/ncurses/curses . If not, edit as appropriate. Just type 'make'
to make the programs.

Warning: you will get some warnings from gcc, from the compilation of
sigscr.c, sweepscr.c and scfio.c. Don't worry, they are only warnings,
the programs work. 

Don't set -Wall in the makefile, the results will be deeply embarassing to
yours truly :-)

Type 'make sysinstall' to install the programs into /usr/local/bin and the
man pages into /usr/local/man/man1. Type 'make localinstall' to install into
$HOME/bin and $HOME/man/man1. If none of these are ok for you then copy
manually or edit the Makefile. Edit the setting of variable PROGS to
customise which programs you install, e.g. you may not wish to install yet
another mixer program so delete smix from the list.


These programs have been tested on

 Linux 1.3.52, with Voxware Sound Driver 3.5 with a MAD16 based soundcard.
 Linux 2.0.33, with Voxware Sound Driver 3.5.4 with a Soundblaster 16
               and glibc


Distribution and Copying

Distribution of this package is covered by the terms of the GNU 
General Public License, version 2. See the file COPYING for further details.
These programs are Copyright (c) 1996-1998 Jim Jackson.


Jim Jackson      jj@scs.leeds.ac.uk
School Of Computer Studies
University of Leeds
Leeds
LS2 9JT 
UK