I have a IR reflected light sensor, an IR LED and a photo-transistor to which I'd like to add some modulation for ambient noise rejection.
My first thought is to just use an IR remote demodulator, like the TSOP58038 or the TSOP4038 which don't have AGC.
But I'd prefer to have lower power consumption (under 0.7mA) and a faster carrier, perhaps 50kHz or more, to allow less phase delay for a faster MCU wake up.
As the MCU is driving the LED from PWM, I have the option to perform synchronous demodulation on the receiver.
Which seems like an XOR/XNOR function, followed by a lowpass.
But I suspect making this low power will be a challenge, especially if I run the the LED at non-symmetrical low duty cycle.
Any suggestions or examples?
I might be searching with the wrong terminology.