CW Doppler Radar Sensor and Motion Demodulation Method Based on Subcarrier Modulation

Abstract

The invention discloses a subcarrier-modulation-based continuous wave Doppler radar sensor and a motion demodulation method. A radio-frequency transceiver chip is connected with a control module; a clock distribution module is connected with the control module and the radio-frequency transceiver chip; and the radio-frequency transceiver chip has transmitting and receiving functions. After clock distribution of a crystal oscillator, two paths of low-frequency sinusoidal signals are generated and one path of signal is transmitted to the control module for digital modulation; the radio-frequency transceiver chip generates two paths of sinusoidal continuous wave radio-frequency carrier signals, one path of signal is a local oscillator signal, and the other path of signal and the low-frequency sinusoidal signals are mixed to generate a subcarrier signal for detection; after under sampling of an echo, the processed signal is transmitted to the control module; filter, mixing, and demodulation are carried and then an anti-trigonometric function is calculated to obtain phase information; a distance and relative displacement information are calculated based on a phase difference; and a motion track is recovered. According to the invention, defects of inherent direct-current excursion and scintillation noises of the traditional zero-intermediate-frequency architecture type receiver can be overcome. While the simple structure and low cost of the zero-intermediate-frequency receiver are kept, the image-frequency suppression function of which the traditional low-intermediate-frequency architecture type receiver is lack is also realized.

Description

technical field [0001] The invention relates to a radar sensor and a detection method, in particular to a subcarrier modulated continuous wave Doppler radar sensor and a motion demodulation method. Background technique [0002] A subcarrier is an electronic communication signal carrier, which is a radio frequency electrical carrier pre-modulated by an analog baseband signal. From the spectrum point of view, it is carried on the upper end of another carrier or on the left and right sides of the carrier, so that the two signals can be effectively transmitted at the same time. At the receiving end, the subcarrier signals of the dual frequency bands are demodulated separately, and the two frequency bands can be used for completely different purposes. In communications, subcarrier channels can be used for a variety of purposes such as radio paging, inventory routing, traffic control signal switching, and background music. [0003] In the field of radar sensing and aerospace mea...

AI Technical Summary

Problems solved by technology

However, the direct down-conversion structure has problems such as DC deviation, local oscillator leakage and flicker noise.

The second is the superheterodyne structure, which requires two down conversions

However, in order to suppress image interference suppression and channel selection, high-Q band-pass filters are required, and they can only be implemented outside the transceiver, thereby increasing cost and size

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