Abstract: Disclosed is a medical care radar system, comprising: a radio-frequency integrated circuit, a first-operation-mode transmitting antenna, a second-operation-mode transmitting antenna, a first-operation-mode receiving antenna set, a second-operation-mode receiving antenna set, a processing device, and an analog-to-digital converter. A field-programmable gate array of the processing device controls the analog-to-digital converter to perform an analog-to-digital conversion without the use of a microcontroller, so that the architecture is simplified and the cost is reduced.

Abstract: Disclosed is a low-pass filtering system having a phase-lock loop comprising a Park transform circuit, a first low-pass filter, a second low-pass filter, an inverse Park transform circuit, a phase-locked loop filter, and a voltage-controlled oscillator. The Park transform circuit, the first low-pass filter, the second low-pass filter, and the inverse Park transform circuit form a phase detector of a phase-locked loop, since the low-pass filter system of the present invention has the phase-locked loop mechanism, the phase and amplitude of a output signal remain the same with those of the original AC input signal.