Wheel Flange Sensor Circuit Design

Develop an electronic circuit that detects a ferrous object in close proximity (20-40mm) to the detector. The detector will have 2 channels, a transmitter coil centrally located and two receivers’ coils spaced approximately 200mm apart. Detection principle based on Beat Frequency Oscillator Detector or equivalent, similar principle to a metal detector. You are an expert in electronics engineering and have experience in similar fields, schematic capture, pcb layout, coil design, rf engineering. Requirements o Local Oscillator ~1Mhz o operate 9-16Vdc o Output per channel, ~5V-12V sine wave 50Khz, modulated by detector circuit, 2 channels for two coil detectors o Minimum 2KHz change in frequency output with 20mm air gap between coil and target o Output, option for current type output o Discrete design, ie no software o Surge/Lightning Protection o Automotive components selection (available from Digikey, Mouser etc) o Electronics to be mounted within the detector Deliverables • Schematics (prefer Altium) • circuit documentation including relevant calculations and simulations • pcb design • BOM