Abstract: Provided are a method and a system for bichromatic laser frequency stabilization based on differential detection of coexisting Lamb-dips and Lamb-peaks under multiple interactions. Based on multiple interactions between a multichromatic laser beam and a quantum resonance system in a Doppler-free configuration, and by setting the relative polarization directions and Raman phases between the pump and probe light which propagate in opposite directions and overlap in space, Lamb-dips and Lamb-peaks signals are generated; and by subtracting one from the other, a Doppler-free quantum resonance signal with high rejection of Doppler-broadening background and common-mode noise is obtained. The Doppler-free quantum resonance signal obtained in the present application has improved contrast and signal-to-noise ratio, and maintained narrow linewidth, making it applicable for precision spectral measurement as well as for laser frequency locking.

Abstract: The invention relates to a differential detection of double-modulation (DM) CPT method and a system for implementing the method of this invention. The method comprises the following steps: Generating a coherent bichromatic light, in which the polarization and the relative phase are synchronously modulated. The DM light interacts with a quantum resonance system and prepares it into a CPT state. Then the polarization of coherent bichromatic light is switched from circular polarization to linear polarization. After interacting with the CPT state prepared in the previous stage, the constructive and destructive quantum interference occur simultaneously. The polarization of the transmitted light from the quantum resonance system is converted and spatially separated. Then two CPT signals, detected by balanced photodetectors, are observed with constructive and destructive interference respectively.

Abstract: The invention relates to a coherent population trapping (CPT) phase modulation and demodulation method and a system for implementing the method of this invention. The method comprises the following steps: Generating a coherent bichromatic light, in which the relative phase between the two frequency components is modulated with proper modulation depth. The phase modulated coherent bichromatic light interacts with a quantum resonance system, and prepares it alternately into two inverted CPT states. Detecting the transmitted light with a photodetector, two inverted dispersive CPT signals in two detection windows are observed. With synchronous phase demodulation, a CPT error signal is obtained, which is used for locking the local oscillator to implement a CPT atomic clock.

Abstract: The invention relates to a differential detection of double-modulation (DM) CPT method and a system for implementing the method of this invention. The method comprises the following steps: Generating a coherent bichromatic light, in which the polarization and the relative phase are synchronously modulated. The DM light interacts with a quantum resonance system and prepares it into a CPT state. Then the polarization of coherent bichromatic light is switched from circular polarization to linear polarization. After interacting with the CPT state prepared in the previous stage, the constructive and destructive quantum interference occur simultaneously. The polarization of the transmitted light from the quantum resonance system is converted and spatially separated. Then two CPT signals, detected by balanced photodetectors, are observed with constructive and destructive interference respectively.

Abstract: The invention relates to a coherent population trapping (CPT) phase modulation and demodulation method and a system for implementing the method of this invention. The method comprises the following steps: Generating a coherent bichromatic light, in which the relative phase between the two frequency components is modulated with proper modulation depth. The phase modulated coherent bichromatic light interacts with a quantum resonance system, and prepares it alternately into two inverted CPT states. Detecting the transmitted light with a photodetector, two inverted dispersive CPT signals in two detection windows are observed. With synchronous phase demodulation, a CPT error signal is obtained, which is used for locking the local oscillator to implement a CPT atomic clock.

Abstract: Provided is a compressor over-load protection control method. The method includes that: the state of a compressor is detected (S101); it is judged whether the compressor is under over-load protection (S102); and when the compressor is under the over-load protection, fluorine shortage protection is shielded (S103). A compressor over-load protection control apparatus includes: a detection unit (10), configured to detect the state of a compressor; a judgement unit (20), configured to judge whether the compressor is under over-load protection; and a shielding unit (30), configured to shield fluorine shortage protection when the compressor is under the over-load protection. Through the method and apparatus, the problem in the relevant art that a fluorine shortage false alarm is easily triggered is solved, thereby achieving the effect of preventing the fluorine shortage false alarm when the compressor is under the over-load protection.

Abstract: A method and a system for monitoring an abnormality at an air outlet of a dehumidifier. The method comprises: identifying whether there is a blockage abnormality at the air outlet of the dehumidifier; after a blockage abnormality has been identified, starting a high wind-level operation of the dehumidifier or controlling air deflectors of the dehumidifier to be reset; after the high wind-level operation has run for a set time period or after the air deflectors are reset, identifying whether the blockage abnormality has been eliminated; and after it has been identified that the blockage abnormality has not been eliminated, controlling the dehumidifier to stop running, and sending out a fault cue. The method and system disclosed can avoid influences on the operation, service life and reliability of the dehumidifier due to a long-term blockage at the air outlet of the dehumidifier.

Abstract: The disclosure discloses a refrigerant control method for a dehumidifier. The method includes that: an environment temperature and an evaporator tube temperature of a dehumidifier are detected; according to the environment temperature and the evaporator tube temperature, a refrigerant leakage amount of the dehumidifier is obtained; and according to the refrigerant leakage amount, it is judged whether the dehumidifier has a refrigerant fault. The disclosure also discloses a refrigerant control apparatus for a dehumidifier.

Abstract: The disclosure discloses a dehumidifier control method and apparatus, and a dehumidifier. The control method includes that: an environment temperature parameter and an environment humidity parameter of a dehumidifier are collected; a working condition of the dehumidifier is determined according to the environment temperature parameter and the environment humidity parameter; a running mode corresponding to the working condition is obtained; and the dehumidifier is controlled to work under the running mode. The control method improves the stability of the dehumidifier.

Abstract: The disclosure discloses a compressor over-load protection control method. The method includes that: the state of a compressor is detected (S101); it is judged whether the compressor is under over-load protection (S102); and if the compressor is under the over-load protection, fluorine shortage protection is shielded (S103). A compressor over-load protection control apparatus includes: a detection unit (10), configured to detect the state of a compressor; a judgement unit (20), configured to judge whether the compressor is under over-load protection; and a shielding unit (30), configured to shield fluorine shortage protection if the compressor is under the over-load protection. By means of the method and apparatus, the problem in the relevant art that a fluorine shortage false alarm is easily triggered is solved, thereby achieving the effect of preventing the fluorine shortage false alarm when the compressor is under the over-load protection.

Abstract: A method and a system for monitoring an abnormality at an air outlet of a dehumidifier. The method comprises: identifying whether there is a blockage abnormality at the air outlet of the dehumidifier; after a blockage abnormality has been identified, starting a high wind-level operation of the dehumidifier or controlling air deflectors of the dehumidifier to be reset; after the high wind-level operation has run for a set time period or after the air deflectors are reset, identifying whether the blockage abnormality has been eliminated; and after it has been identified that the blockage abnormality has not been eliminated, controlling the dehumidifier to stop running, and sending out a fault cue. The method and system disclosed can avoid influences on the operation, service life and reliability of the dehumidifier due to a long-term blockage at the air outlet of the dehumidifier.