array receiver of ultrasonic transducer

Mainly introducing the connection mode of the ultrasonic transducer array (auxiliary receiver) output port. The next chapter studies the design problem of the receiving and transmitting circuit of the disc-type piezoelectric transducer (main transducer), The circuit-assisted receiver array consists of 16 transducers, each with two external wire is acting as signal and ground.The echo signals in the range act on the auxiliary receiver array, and the adder has a signal output. In order to increase the signal-to-noise ratio of the auxiliary receiver, a band-pass filter is having a center frequency of 27.5 kHz and a quality factor of 5khz may be connected to the output of the second-stage.Then, it is added to the output signal of the band pass filter in the main receiving circuit transducer. In this way, the combined ultrasonic depth sensor can receive an echo signal of 22-29. 5 kHz, which widens the bandwidth of the air-mediated ultrasonic transducer.

The speed range assumes that the target reflection surface is facing the ultrasonic depth sensor transducer, then the doppler frequency offset f respectively represent the frequency of the echo signal and the transmitted signal; v represents the relative speed between the ultrasonic probe; c represents the ultrasonic wave in the air speed of propagation in the medium. When the target is far away from the ultrasonic probe (the distance is increased), }d is a negative value; otherwise, the target is close to the probe (the distance is reduced) and fd is a positive value. When the target is close to the probe, the combined ultrasonic probe can measure the maximum speed of the moving target. It can be seen that the combined transducer can be used to measure the moving target speed range of 50 -156km/hr. Here, the lower operating frequency is set to 23. 5 kHz, which is beneficial to expand the range and speed range of the ultrasonic transducer, but has a slight influence on the impedance matching effect.