Ostapenko

pp. 209-229

Existing shock sensors for car protection using the sensitive elements (SE) of piezoelectric, microphone and electromagnetic types and the analogue circuits of signal processing, have a number of essential shortcomings, such as "false" operations, instable temperature characteristics, nonlinear adjusting characteristic, and inconvenient control via variable resistors. The article considers issues to design the two-zone digital shock sensors with a SE of electromagnetic type. It offers a SE design, a circuitry solution, and algorithms of signal processing, which allow a remote control of prevention and alarm zones (with 16 gradations of sensitivity) and an algorithm for self-adapting to repeating external impacts. The method has been developed to form the basic levels of digital comparators for each gradation of sensitivity. Using this method enables the sensor to have the straight-line adjusting characteristic. Prospects for using the 3-axial micromechanical accelerometers as a SE of the shock sensors are proved.

The existing analog circuit-based microwave sensors for car alarm systems have high power consumption and high level of intrinsic noise, causing "false" alarm of response sensors; non-stable temperature characteristics that require readjusting the sensor during the transition from the summer season to the winter one; adjusting the nonlinear characteristics and uneasy adjusting with variable resistors.The paper concerns the issues of designing the two-zone digital microwave sensors. It proposes a circuitry and algorithms for digital signals processing. This allows the 6-8 times reduction of power consumption, cut of noise level in half thereby increasing the sensor sensitivity and implementing a remote setting of warning and alarm zones (16 levels of sensitivity) and an algorithm of self-adaption to the repetitive external actions. The paper proposes a method for generating the reference levels of digital comparators at each gradation of sensitivity to linearize the output characteristic of the sensor.