As today's practitioners and educators, we bear responsibility for training our students to achieve the deep conceptual understanding that they require to be the next generation of signal processing innovators. This article describes our work using think-aloud problem-solving sessions to reveal student misconceptions and to design improved conceptual problems for use in active learning classrooms. In addition, we present recently updated Signals and Systems Concept Inventory (SSCI) data demonstrating that courses incorporating active learning pedagogy produce larger gains in students? conceptual understanding of signal processing.