Table 5.6-9: Aib-Hydro Pin Designations - Moog 903 User Manual

903-0623-00 Rev. A
Although the card is configured to operate with two-wire, un-amplified hydrophone inputs, the hydrophone
plug-in may be factory modified to provide +12V to an external hydrophone pre-amplifier on a third
conductor and bypass the gain of the internal pre-amplifier.
Front panel pin designations for the AIB-HYDRO plug-in modules are given in the table below.
*The chassis pin is normally left open on the mating connector.
Frequencies from 16 Hz to 28 kHz (-3 dB points) are passed through the system, though frequencies
slightly outside this range may be transmitted if the added loss can be compensated by additional S1
gain. If low frequency noise pick up (typically 50 or 60 Hz) is introduced by improper shielding, the lower
pole frequency may be raised by adding a shunt resistor across pins 3 and 4 to attenuate the lower
frequencies. The chassis pin on the WAGO connector should be connected to the shield of the
hydrophone cable.
The analog signal on the input board (remote end) is digitized at 73 kilosamples per second with a 12-bit
resolution after amplification and reconstructed at the output board (console end) with no additional gain.
(Switch bank S1 is not active when the hydrophone board is configured for output.) Output impedance is
approximately 34 ohms, which is suitable for high impedance loads and is even capable of directly driving
8-ohm speakers, although with a corresponding loss in output power. Maximum output level is limited to
2 Vpp, yielding a dynamic range of roughly 66 dB.
Focal Technologies Corp.

Table 5.6-9: AIB-HYDRO Pin Designations

Pin Designation
1 Chassis* (optional)
2 N/C
3 - Signal (GND on output)
4 + Signal
Model 903 User's Guide, FMB-X-2.5 Version
Page 5-32