| 摘要 |
The invention relates to a device for controlling a material, the device including at least one transmitter for transmitting an electromagnetic signal at a carrier frequency Fp to illuminate the material and one receiver for receiving the electromagnetic signal, wherein the device further includes a first modulator for modulating the electromagnetic signal at a frequency Fm1, the first modulator being arranged, on the signal path, between the transmitter and the material in order to spatially sample the emitted electromagnetic signal; second modulator for modulating the electromagnetic signal at a frequency Fm2, the second modulator being arranged, on the signal path, between the material and the electromagnetic signal receiver in order to spatially sample the electromagnetic signal passed through the material. |
