Design And Implementation Of Multi-channel Receiver For Multi-beam Bathymetric Sonar

Multi-beam bathymetric sonar is a device that can detect the depth of the underwater,which is widely applied in the area such as seafloor topography and geomorphology detecting and marine environmental monitoring. As an important part of sonar equipment, the performance of receiving system affects the performance of sonar equipment directly.The history and current situation of Multi-beam bathymetric sonar is introduced. The system composition and the principle of Multi-beam bathymetric sonar is analyzed. Then the indicators of forty channels in the receiving circuit and the plan of the hardware system is proposed. The signal noise is introduced and the equivalent input noise model of the circuit is studied, The low noise receiving circuit is ultimately designed and realized. In order to design the circuit of controllable gain,the different chips is compared, confirming the AD8336 at last.The structure of the MFB and reduced quadratic form is introduced and compared while the MFB band-pass filter and AD8032 is accepted. Fixed gain amplifier circuit and the consistency of the channels is also considered . In order to reduce the ripple noise of the switching power supply, the filter is designed. The cooling fin should be designed considering the issue of consumption. Based on the circuit schematic diagram, I complete the design of PCB of six layers and weld the circuit board.The tests of the receiver of forty channels that are accomplished meets the requirements of the design, including enlarging itself by times, pass-band, consistency, noises and so on.The gain is adjustable between thirty decibels and one hundred and thirty decibels and the pass-band is fourteen kilohertz. The center frequency is one hundred kilohertz. The amplitude error is ± 0.15dB and phase consistency is 20 absolutely. The voltage value of the equivalent input noise is less than three microvolts. The value of the ripple noise of switching power supply is reduced to thirteen millivolts. The test is verified to offer a good stability of the receiving system after working for a long time.