ADPD6000 Multimodal Sensor Front End Analog Devices Inc. ADPD6000 Multimodal Sensor Front End is highly integrated and intended for measuring various vital signals. The AFE optical channel is designed as an optical transceiver, stimulating up to four light emitting diodes (LEDs) and measuring the return signal on four separate current inputs. The signal chain rejects signal offsets and corruption from asynchronous modulated interference, typically from ambient light, eliminating the need for optical filters or externally controlled dc cancellation circuitry.