Analysisi On Anti-noise In Front End Of Sonar System And Design Of Phased-array Receiver

Sonar is a essential precise instruments for the ship and submarine, the precision affect the security of ship and submarine. The electromagnetic environment inside of ship is complex, To the system, the deficiency of electromagnetic compatibility can bring critical effect. The practice proved the electromagnetic of the connector box and interconnection cable of complicated system is the weakest link. This is a widespread and difficult to avoid problem. This paper will analyses the anti-interference of sonar system front-end and the design proposals, research for the phased array receiver design.First, at the different cable grounding condition, utilizes electromagnetic theory derivation the induced current generation in the cable, and sum up the best grounding structure at the different external field. Second analyses the effect on 1.5M log integrated response of the cable length, emulates the effect on log receive and transmit signal of the cable length, and the transmitter matched impedance. Verify the effects on experiment. Third, utilizes the electromagnetic wave transmission theory, get the calculate methods of metals shielding ratio at different external field, emulates the relationship between shielding ratio and metals thickness, show the basis for choice shielding material. Designs the shielding shell for the image sonar receiving module, and verified in experiment, designs wide-band and narrow-band phase-controlled Doppler receiver, use capacity coupling parallel resonance circuit achieve the filtering, the indexes all reach the standard.Experiments manifest aforementioned all reach the expert demand, phase-controlled Doppler receiver accomplished the function requirement, with transmitter and signal processor coordination running well in experiment.