| 摘要 |
A system 100 is provided that includes a Doppler radar unit 102 that transmits a first electromagnetic wave 106 having a first frequency, which a test system 104 converts to a first electrical signal having the first frequency. The test system 104 generates a second electrical signal having a second frequency, and mixes the first and second electrical signals to produce a third electrical signal having a third, sum or difference frequency. The third frequency represents a Doppler-shifted frequency caused by reflection of the first electromagnetic wave 106 by a target at a distance from the Doppler radar unit 102. The test system 104 converts the third electrical signal to a second electromagnetic wave 108 having the third frequency, and transmits the second electromagnetic wave 108 back to the Doppler radar unit 102 for calculation of a speed representing that of the target as a function of the first and third frequencies, from which the Doppler radar unit 102 may be calculated/certified. |
