Noise suppression using signal strength ratio metric modulated light

An apparatus, comprising:

• a light source interface communicatively coupled to a light source in a photoelectric smoke detector;
• a light sensor interface communicatively coupled to a light sensor in the photoelectric smoke detector;
• a control circuit communicatively coupled to the light source interface and the light sensor interface, the control circuit to:
• generate a signal strength ratio metric modulated signal at a modulation depth;
• send the signal strength ratio metric modulated signal to the light source interface to cause the light source to emit a signal strength ratio metric modulated light beam;
• and
• receive a reflected light signal from the light sensor via the light sensor interface, the reflected light signal including a signal indicative of a reflection of the signal strength ratio metric modulated light beam and a signal indicative of a noise light.