BODC HEADED DOCUMENT NO. 41614 Applies to BODC Series Ref. Nos.: 29842, 29854, 29866, 29878, 29891, 29909, 29910, 29922, 29934 Aanderaa Pressure Recorder The Aanderaa recorder uses a Digiquartz type 2-300a quartz crystal pressure transducer. The pressure sensor consists of a convoluted bellows linked to a 40kHz quartz crystal resonator coupled by piezoelectric action to an electronic resonator. Data are recorded on to 0.25 inch magnetic tape on an Aanderaa data logger in the same case. A quartz crystal clock is used for controlling the sampling interval. The data are recorded as 10 bit binary words in serial form with the frequency count from the sensor stored as the most and least significant counts.