Broadband Transmitter Design And Implementation

Sonar transmitter is an important part of sonar system.It determines the range of sonar,resolution and other important parameters.It seems very important that the sonar transmitter could lauch broadband signal. Broadband lauching means the singal could carry more information, so it is the development trend of sonar transmitter.According to the needs of project, this paper designed two broadband transmitter. They are respectively the fish finder transmitter and parametric array transmitter.Fish finder transmitter is a kind of fishery helping equipment based on underwater acoustic technology. Multi-beam and broadband is very important to the fish finder transmitter.It use the principle that Sonar signal launch out to fish target and receive the echo signal, using the echo signal could measure the diatance between fish target and boat.According to the sonar array have the characteristics of transmitting and receiving directivity,which determined the location of the fish. According to the size of the reflected signal and the signal strength, which can roughly determine the number of fish. Fish finder transmitter using FPGA as the core of the signal source, by the signal source to produce different types of signal.By the class D amplifier signal power amplifiered and then loaded into the transducer array. By changing the duty ratio control signal output power. Select suitable power device,control circuit noise. Aiming at the condition of the transceiver design a transmit-receive circuit.Parametric array transmitter as excitation system of parametric array, needs to form strong power in the water acoustic pulse, and thus generate superior difference frequency signal. And in order to guarantee the high conversion efficiency of the difference frequency singal,broadband emission parameter signal is one of the most important prerequisite.Parametric array transmitter using the existing signal module, produce different envelope in the form of the CW signal to drive the class B power amplifier circuit. By controlling the amplitude of the output signal to control the output power. Research the principle of class B amplifier and calculate the parameters of the power amplifier circuit. Select the appropriate power amplifier chip, transformer, peripheral circuit,and then make its has the abilityof linear amplifier and broadband emission.Respectively in channel pool and field testing fish finder transmitter. In the channelpool test its output power and output efficiency.By changing different transmission frequency, test its emission source level. In songhua lake test, verify the stability of the transmitter. Testing the parametric array transmitter in the pool, testing its emission source level under different frequency,verify the transmitter of the cooling performance and system stability...