A practical magnetic bubble AND-OR gate

The design and operation of a magnetic bubble AND-OR gate are reported. Operation at 100 kHz in a 25 Oe rotating field with 28.2 μm circuit periodicity was achieved with about 50 percent of the free bubble bias field margins. A transfer pulse is used to divert bubbles from a propagation path which delivers the AND output tO one which delivers the OR output. The transfer is defeated by the presence of a bubble in the appropriate cycle of the OR path. The AND bubble is then delayed by one cycle instead of being transferred. This frastrated transfer strategy was devised to circumvent the restrictive bias field limitations in the operation of previous logic circuits.