optical heterodyne receiver
光频外差接收器

• passive laser beam comunication satellite
• passively Q-switch laser
• passive mode-locking
• passive night-vision device
• passive otpical filter
• passive otpical omponent
• passive phtoresistor
• Passive Pixel Sensor
• passive Q-switch
• passive reflector
• passive retrodirective element
• passive solid region
• passive switch
• passivity
• path
• path difference
• path finder
• path length
• path-length error
• path mismatch
• path of ray
• pathway
• patrol camera
• pattern
• pattern evaluation