OSCILLOSCOPE
by Robert Horsfall
from Sinclair User #15 (June 1983)

Oscilloscope uses the IN function to scan the MIC and EAR sockets. It
then draws the response on the screen, acting like an oscilloscope. By
recording your voice on cassette, playing that back while the program is
running, you can obtain a representation of your voice pattern on-screen.

The program was written for the 16K Spectrum by Robert Horsfall of
Eastburn, Yorkshire.