Multiplexing readout circuit and method for electromagnetic inspection array probe

A readout method for an electromagnetic inspection system for nondestructive testing of a test object, the electromagnetic inspection system comprising a plurality of sensors configured to generate a respective plurality of response signals indicative of an electromagnetic response induced from the test object, the readout method comprising:

• receiving the plurality of response signals from the plurality of sensors;
• performing a bandlimiting operation on the plurality of response signals to produce a plurality of bandlimited signals;
• and
• performing a time-division multiplexing operation on the plurality of bandlimited signals to produce a time-division multiplexed (TDM) signal comprising a sequence of frames outputted at a TDM frame rate, each frame comprising a plurality of time slots, each time slot being assigned to a respective one of the plurality of bandlimited signals,
• wherein the bandlimiting operation is carried out based on the TDM frame rate to attenuate aliasing artifacts in the TDM signal.

An electromagnetic inspection system for nondestructive testing of a test object, the electromagnetic inspection system comprising:

• an emitter unit configured to generate an excitation signal to induce an electromagnetic response from the test object;
• a receiver unit comprising a plurality of sensors configured to sense the electromagnetic response induced from the test object and generate a respective plurality of response signals from the sensed electromagnetic response;
• and
• a readout circuit comprising:
• a plurality of anti-aliasing filters, each anti-aliasing filter being configured to receive the response signal from a respective one of the sensors and to bandlimit the respective response signal to produce a respective one of a plurality of bandlimited signals;
• and
• a time-division multiplexer coupled to the plurality of anti-aliasing filters and configured to multiplex the plurality of bandlimited signals into a time-division multiplexed (TDM) signal, the TDM signal comprising a sequence of frames outputted at a TDM frame rate, each frame comprising a plurality of time slots, each time slot being assigned to a respective one of the plurality of bandlimited signals,
• wherein the plurality of anti-aliasing filters is configured to operate based on the TDM frame rate to attenuate aliasing artifacts in the TDM signal.