From the GitHub profile page: github.com/mahapo/zcp-transmitter

Speech as radio pulses, in the browser. Audio (microphone, eSpeak text-to-speech or a file) runs through a filter chain, every zero crossing of the result becomes one short RF pulse, and an SDR sends the pulse train. It is a port of a GNU Radio desktop app, and its chain reproduces that app's output: of the 74 configurations of the app's reference catalog, 56 come out bit for bit and the other 18 are identical until the speech has ended.

Run it live in your browser, right now: https://mahapo.github.io/zcp-transmitter/

Ported from the original codebase: https://github.com/OpenV2K