Is there any free tool to generate a tone with gradually increasing pitch?

The sox utility can do this. To generate a WAV file:

sox -n output.wav synth 600 sine 20-16k

Mind you, this will generate a 100 MB WAV file, since it defaults to a 48 kHz sampling rate. Since you need a maximum frequency of 16 kHz, you could get away with a 32 kHz sampling frequency instead:

sox -r 32k -n output.wav synth 600 sine 20-16k

This file will be only 74M. Or you could use MP3 and get it down to 3.5 MB:

sox -r 32k -n output.mp3 synth 600 sine 20-16k

A breakdown of how this works:

• The -r 32k specifies the 32 kHz sampling rate.

• The -n output.wav specifies the output filename.

• 600 is for 600 seconds (10 minutes).

• The 20-16k is the frequency range (20 Hz to 16,000 Hz).

If you just want to play it directly, you can do this:

play -n synth 600 sine 20-16k

More information here:

• http://sox.sourceforge.net/sox.html

• http://sox.sourceforge.net/Docs/Readme

• http://sox.sourceforge.net/Docs/Features

Audacity can do this. Select Generate → Chirp....

The default sampling frequency is 44.1 kHz, which can be adjusted under Edit → Preferences... → Quality → Sampling → Default Sample Rate

Be careful not to hurt your ears when playing it back!

This does almost everything you need (save for the length): http://heliso.tripod.com/download/generator/dsg.htm

Another one, also with a length limitation: http://softsolutions.sedutec.de/multisine.php

If you use a linear sweep, you can simply divide your 10 minutes into whatever is possible with the above tools and then splice the sound together in Audacity afterwards.