Analog Hardware Design Of 300kHz ADCP Based On Conventional Array

ADCP(Acoustic Doppler Current Profilers)is a kind of flow measurement equipment developed in the 1980 s.At present,ADCP is widely used in the investigation of flow field structure in ocean rivers and other fields,and in the measurement and test of flow velocity and flow rate.The ADCP designed in this paper is a new type of equipment for speed measurement and navigation of a naval warship.This paper mainly completes the design of 300 kHz ADCP hardware circuit,including receiver and transmitter,and also discusses the Doppler velocity measurement method.The transducer used in this paper is a 300 kHz conventional array transducer with four elements,so the receiver and transmitter each contain four channels.The transmitter type is a full bridge class D power amplifier based on IR2110 S driving circuit,which combines transformer to transform the signal voltage to achieve the target sound source level of 220 dB.In addition,magnetic isolation circuit is designed in the front stage of transmitter to ensure the relative independence of each circuit in the system.The design of receiver includes basic circuit units such as amplification,filtering and mixing.The gain amplifier circuit includes two-stage controllable gain amplifier circuit,one-stage gain selection circuit,one-stage fixed gain amplifier circuit and one-stage gain compensation circuit.The filter circuit is divided into two stages.The front stage uses RLC resonance to filter the signal amplified by the controllable gain amplifier circuit.The central frequency is 300 kHz,and the design bandwidth is 260 kHz to 340 kHz.The post-stage filter is designed as a low-pass filter,which is used to process the mixing clutter and filter out the high-frequency components such as frequency doubling to get Doppler frequency shift signal with a cut-off frequency of 42 kHz.In addition,the mixing circuit uses analog switches to multiply the received signal and the reference signal,and works with the post-stage low-pass filter to get Doppler frequency shift signal.The power supply circuit of the system uses AC/DC and DC/DC modules to supply power to transmitters and receivers.After the transmitter and receiver are designed and debugged,the tank test is carried out.Experiments show that the transmitter can drive the transducer to emit signals with a sound source level of 220 dB and the receiver works well and stably,and the parameters of each part meet the design specifications.