Tone Gen Pro

You use to be able to go over 20khz?

This is a great app for generating tones but has a very useful feature: the ability to generate clicks with a custom duty cycle. In particular, the app can replicate the precise 40Hz tone shown to have therapeutic benefit in mouse models of Alzheimer’s Disease. Just navigate to ‘clicks’, select On-Off frequency of 40 Hz, On frequency of 2000 Hz and On-time of 0.001 sec (4%).

I searched through all the other signal generators to find one that contained a dc offset. This was the only one. Really great control on the app!