Provided by: siggen_2.3.10-11_amd64 bug

NAME

       siggen - an Ncurses based signal generator program

SYNOPSIS

       siggen [options] [waveform [freq]]

DESCRIPTION

       siggen  is  a  simple signal generator program, with an Ncurses based user interface, that
       can digitally generate standard waveforms on the LINUX  /dev/dsp  device.   8  or  16  bit
       samples can be generated depending on the hardware.

       siggen allows two independent waveforms to be generated.  In stereo the two signals appear
       on different channels. In mono the two signals are  digitally  mixed  onto  the  one  mono
       channel.

       The frequency is specified as an integer number of Hertz. Fractional Hertz frequencies are
       not supported. Of course, only frequencies  less  than  half  the  samplerate  (number  of
       samples/sec)  are  accurately  meaningful.  Higher frequencies can be specified, but don't
       expect to hear them!

       On screen values for individual fields can be locked to prevent  accidental  changes.  The
       unlock facility unlocks all locked fields.

       Corresponding values for the 2 channels can be set to track, the values are made equal and
       a change to one causes a change to the other.  e.g. making the frequency values track will
       make  both  channels  the  same  frequency,  and  altering  one  freq.  value  alters both
       simultaneously.

       The waveforms that can be generated are:

       sine   A standard sine wave

       cosine a sine wave with a 90 degree phase shift

       square a standard square wave with a 50% mark space ratio

       triangle
              a linear rise from 0 to peak, thru' 0 to negative peak, and back to 0

       sawtooth
              a ramp waveform with 'infinitely' fast flyback (:-) An ideal oscilloscope  timebase
              signal.

       noise  This  is  weak.  All  it  consists  of  is  one second of pseudo-randomly generated
              samples, played repeatedly. I'd love to do proper white/pink  noise,  but  I  don't
              know  enough,  and  I  don't  think  the  structure  of the program is conducive to
              accurate noise generation.

       pulse  A square waveform where the mark/space ratio (as a percentage)  can  be  specified.
              The default value is 10% (mark/space ratio of 1:9).

       A lot of thought has gone into the algorithms for generating the waveforms.  I believe the
       sin/cos wave to be very pure (modulo your sound card :-), but I don't have access to a THD
       meter  to  measure  it.  For  best  signal  accuracy leave the gain setting at 100(%). The
       generator will then make the wave's peak value fit the maximum digital values allowed. Use
       a mixer program to control the output volume, or an external attenuator.

       The  gain  factor  option  can  be useful for simulating a signal that has been subject to
       clipping, by specifying a gain of > 100%. In fact  a  trapezoid  signal  can  be  made  by
       generating a clipped sawtooth wave. The greater the gain, the closer the signal approaches
       a square wave (the rise and fall times decrease).

       siggen ordinarily generates one seconds worth of 1 Hz samples at the specified samplerate,
       for each waveform, and generates frequency F by circularly sampling every Fth sample. Each
       buffer fragment is generated for the parameter(s) set  at  that  moment.  Buffer  fragment
       sizes  are  set  so  that  aprox.  10  fragments/sec  are generated. Changing a generation
       parameter, e.g. waveform, frequency, gain, will impact the next buffer fragment generated,
       and hence changes appear to be almost immediate.

       The  -res  option  can  be  used to make siggen generate signals with 0.1Hz resolution, or
       0.01Hz resolution. However be warned at 0.1Hz resolution the basic waveform sample buffers
       generated are each 10 times (and at 0.01Hz resolution 100 times) as big as the samplerate.
       It typically requires 5.5Mbytes  of  memory  to  run  at  0.1Hz  resolution,  16bit  32000
       samples/sec.  and  55Mbytes  of  memory  to run at 0.01Hz resolution. Because of the large
       buffer sizes, the initial waveform calculation time can also be  lengthy.   Remember  also
       that   the   waveforms   are  re-calculated  whenever  the  playing  parameters,  8/16bit,
       mono/stereo, samplerate are changed.

       If your sounds periodically 'breaks' up with clicks or breaks, it is usually a  sign  that
       siggen  is  not being scheduled sufficiently often. Either increase the priority (see nice
       et al.), kill off other processes, get a faster processor, or increase the number of audio
       buffer  fragments  that siggen uses. This last will make siggen respond more sluggishly to
       changes in generation parameters.  syslogd and crond are two  processes  that  I've  found
       useful to kill off - YMMV.

       Defaults
              output  to  /dev/dsp,  22050  samples/sec,  stereo if stereo card else mono, 16 bit
              samples if possible, else 8 bit, 3 audio buffer fragments.

CONFIGURATION FILES

       Three possible configuration files can be used: a LOCAL config file  (usually  in  current
       directory), a HOME config file in user's $HOME directory and a GLOBAL config file.

       All the siggen suite of programs are compiled with the names of the config files built in.
       By default the configuration files are:

       ./.siggen.conf
              is the LOCAL config file.

       $HOME/.siggen.conf
              is the HOME config file.

       /etc/siggen.conf
              is the GLOBAL config file.

       siggen -h
              will indicate which config files will be searched for.

       The config files do not have to exist. If they exist and are readable by the program  they
       are used, otherwise they are simply ignored.

       The  config  files  are always searched for configuration values in the order LOCAL, HOME,
       GLOBAL. This allows a scheme where the sysadmin sets  up  default  config  values  in  the
       GLOBAL  config  file,  but  allows a user to set some or all different values in their own
       HOME config file, and to  set  yet  more  specific  values  when  run  from  a  particular
       directory.

       If  no configuration files exist, the program provides builtin default values, and most of
       these values can be set by appropriate command line switches and flags.

       See siggen.conf(5) for details of the configuration files.

       siggen  looks  for  configuration  values  BUFFERSPERSEC,  CHANNELS,  DACFILE,  FRAGMENTS,
       RESOLUTION, SAMPLERATE, SAMPLESIZE, VERBOSE, VI_KEYS.

       BUFFERSPERSEC
              The  aprox. number of sound buffer fragments to play every second (Sound buffersize
              is always a power of 2).

       CHANNELS
              sets the number of channels, see '-c' option.

       DACFILE
              allows the name of the DAC/DSP/PCM device to be changed from /dev/dsp

       FRAGMENTS
              The number of Audio Buffers to configure in the driver.

       RESOLUTION
              The minimum change possible to the frequency setting. Only 3 values allowed: 1Hz  ,
              0.1Hz or 0.01Hz

       SAMPLERATE
              sets the number of samples/sec for the DAC device

       SAMPLESIZE
              sets whether 8 or 16 bit samples to be generated

       VERBOSE
              sets whether or not to run in verbose mode.

       VI_KEYS
              if set then the VI cursor moving keys "HJKL" are enabled

OPTIONS

       -h     display usage and help info

       -BPS n configure to play aprox. n audio buffers per second.

       -C configfile
              Use configfile as the LOCAL configuration file.

       -NB n  set number of audio buffers to n

       -v     be verbose

       -s samples
              generate with samplerate of samples/sec

       -8|-16 or -b 8|16
              force 8 bit or 16 bit mode.

       -1|-2  mono or stereo

       -res n set resolution of frequency generation. Valid values are: 1Hz, 0.l1Hz or 0.01Hz

EXAMPLES


FILES


SEE ALSO

       signalgen, swgen, tones, sweepgen, siggen.conf

BUGS


COPYING

       Copyright 1995-2008 Jim Jackson

       The  software  described  by  this  manual  is  covered by the GNU General Public License,
       Version 2, June 1991, issued by :

              Free Software Foundation, Inc.,
              675 Mass Ave,
              Cambridge, MA 02139, USA

       Permission is granted to make and distribute verbatim copies of this manual  provided  the
       copyright notice and this permission notice are preserved on all copies.

       Permission  is  granted  to copy and distribute modified versions of this manual under the
       conditions for verbatim copying, provided  that  the  entire  resulting  derived  work  is
       distributed under the terms of a permission notice identical to this one.

       Permission  is  granted  to  copy  and distribute translations of this manual into another
       language, under the above conditions for modified versions, except  that  this  permission
       notice may be included in translation instead of in the original English.

AUTHOR

       Jim Jackson

       Email: jj@franjam.org.uk