Abstract

Ultrasonic sensing involves using sound waves at frequencies higher than human hearing which is typically above 20KHz to detect object, measure distances or sense presence or absence of any material. Ultrasonic sensing works by emitting ultrasonic wave signal from a transmitter which travels through the medium and as it hits any object the signal partly reflects back, some get absorbed while remaining permeates through the object. This reflected or permeated wave is then detected by the receiver and processed to extract the useful information like the time of flight or the amount of attenuation the signal suffered as it traveled through the material. This article shows how Logarithmic detector like LOG300 can be used in the receive signal chain to process the signal from the ultrasonic receiver for applications like double paper sheet detection, material detection, bubble counter or detection in fluid, material detection and distance or proximity detection.