Characterisation of magnetic bubble detector performance

The motion of strip domains through two designs of detector stacks has been measured in the frequency range 100kHz to 400kHz. One of the detector stacks has interconnections at alternate ends of the arms of the chevrons (type 1), the other is connected at the (incoming) end and just past the centre (type 2). For both detectors the strip position/drive phase plot differs from that previously reported for nonconnected chevrons. Through a type 1 detector typically an extra 10° phase lag is seen on the transition from the input to the centre, and a rather larger (35°) extra lag after moving to the output end. A type 2 sensor has comparable input lag, but the output transition is identical to that in normal chevrons. Appreciable variations in the phase behaviour are observed, depending on the polarity of sensor current in accordance with the vertical fields set up. The current can also help to suppress the onset of a random strip oscillation, liable to occur in a type 2 sensor above 300kHz. The signal characteristics are briefly related to the phase behavior.