From chirps to random-FM excitations in pulse compression ultrasound systems

Pulse compression is often practiced in ultrasound Non Destructive Testing (PDF) systems using chirps. However, chirps are inadequate for setups where multiple probes need to operate concurrently in Multiple Input Multiple Output (PDF) arrangements. Conversely, many coded excitation systems designed for PDF miss some chirp advantages (constant envelope excitation, easiness of bandwidth control, etc.) and may not be easily implemented on hardware originally conceived for chirp excitations. Here, we propose a system based on random-FM excitations, capable of enabling PDF with minimal changes with respect to a chirp-based setup. Following recent results, we show that random FM excitations retain many advantages of chirps and provide the ability to frequency-shape the excitations matching the transducers features.