where is this "rob base" sound from?

[marcuse]

dear forum,

maybe you know the song "get on the dancefloor" by rob base. i always wondered where the rave-ish kind of sound is from.

http://www.file-space.net/files/rave_sound_sample.mp3

it was used very often by similar artists at that time (about 1987-89). i seems to be a synth sound (alpha juno, dx7,...) but then commonly used as a sample. anyone got some information about the origin of this sound or a hint where to get it from?

kind regards,
marcus