berryh@udel.edu (John Berryhill) (03/01/90)
Teddy uses a stereo head with music on one channel and data on the other. Not having a storage scope handy, it's tough to get a good look at the data channel except for those moments when the tape holds one facial expression long enough to get a picture of it with the scope camera. The data packets are about 8 milliseconds long with 4 milliseconds between them. Inside each packet is some sort of triangle wave that has a variable delay at the upward zero crossing, i.e. /\ /\ /\ / \ / \ / \ and so forth (about 8 per packet) 0---- \ /-- \ /--- \ / \/ \/ \/ Has anybody out there managed to figure out what sort of modulation this sucker uses? I've been able to get him to partially close his eyes and hold his mouth wide open using two function generators (a square-modulated plain triangle wave recorded on audio tape), but twiddling the frequencies and duty cycle doesn't seem to do anything for him. -- John Berryhill 143 King William, Newark DE 19711
markz@ssc.UUCP (Mark Zenier) (03/03/90)
In article <12595@nigel.udel.EDU>, berryh@udel.edu (John Berryhill) writes: > > The data packets are about 8 milliseconds > long with 4 milliseconds between them. Inside each packet is some > sort of triangle wave that has a variable delay at the upward zero > crossing, i.e. > ... > Has anybody out there managed to figure out what sort of modulation > this sucker uses? One of the winners in the Circuit Cellar Ink design contest last year was a project for generating Teddy Ruxpin data. They havn't published the details yet. It looks like the pulse postion modulation used in radio control, where the analog value is encoded in the time between pulses. markz@ssc.uucp