SPEM, sistema pulso-eco microcontrolado para geração e medição de campos ultra-sonicos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

In order to obtain more reliability in the processing of information obtained by ultrasound radiation, it is very important to understand the basic principIes of ultrasound wave generation, interaction with and propagation through different media. This can be partially achieved with suitable equipments and a good knowledge of its working conditions. In an effort to measure and study ultrasonic features of different materiaIs, we have developed a Pulse-Echo Microcontrolled System (SPEM) for generation and reception of RF signals in the range ofultrasound medical diagnosis. The hardware consists oftransmission, reception, control and interfacing circuits. The control and interfacing circuits were developed with a Motorola MC68HCII-Al microcontroller and proper circuitry to implement the IEEE Standard 488 (General Purpose Interface Bus - GPIB). The SPEM is fully controlled via remote mode through the GPIB interface, and permits local control with proper keys in the front pane!. Special software has been developed Ín C-language to run in an IBM-PC compatible microcomputer, working as GPIB controller and equiped with a HPIB 82335A interface model of Hewlet-Packard. The SPEM control software has been written in MC68HC11 assembly language. The transmitting circuit emits pulses 330 ns wide with an amplitude that may be controlled from 15 V to 200 V or pulses 200 ns, 300 ns, 400 ns, 500 ns, 600 ns and 700 ns wide with an amplitude controlled from 2 V to 28.4 V. The receiving circuit amplifies RF signals in the range of 10 kHz to 10 MHz from 0.6 V/V to 3730 V/V (-4.4 dB to 71.5 dB) in 25 steps. The system was tested with a 1 MHz transducer facing an aluminun rod, both immersed in water. Ultrasound waves have been generated and received by the system which has presented good performance. The results have shown that the equipment may be used for research purposes in the Ultrasound Laboratory of the Centre for Biomedical Engineering at Unicamp

ASSUNTO(S)

ultra-som controle automatico ultra-som na medicina

ACESSO AO ARTIGO

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