| Life detection radar is a Doppler radar, which can be used to search survivals, spy concealed criminals, observe patients and other conditions.The signal processing board was devised in the paper, based on the characteristics of the reflected microwave from human body. 1. The interface circuits between the board, microwave parts and computer were designed, in order to transmit signals securely and not to influence each other. 2. Analog filter amplifier circuits with steady low-frequency performance were schemed out, which not only restrained the disturbance outside the filter passband, but also amplified the message signals to some extent that met the requires of ADC. 3. The 16-bit digital signals were converted into by AD7675, then saved and sent by the kernel control unit, Atmegal28, which predigested the control circuit. 4. The communication has two processes, sending the digital data to computer and receiving the instructions from PC. The wireless transport protocols used between the board and the computer was established, which guaranteed the whole messages communicated with computer credibly and sequentially. 5. For the needs of the voltage and power, the power control circuit made the output voltage with little ripple and made the system work credibly. 6. The system was provided with a battery inspection device, which prevented the data dropping suddenly. Furthermore, many anti-interference techniques introduced in analogue preprocessor to deal with the analogue signal were summarized.The experiment shows the most parameters of hardware design for life detection radar can meet the system requirements. It has the characteristics as follows: good filter effect, low noise and cost power, suitable power control circuit, and so on. |
PDF Full Text Request