ALGUETA MIGUEL , José María

Two approaches to implement variable gain amplifiers based on Miller op-amps are discussed. One has true constant bandwidth while the other has essentially reduced bandwidth variations with varying gain. Servo-loops and ac coupling techniques with quasi floating gate transistors are used to provide a bandpass response with very low cutoff...

A low-power ultrasonic communication front end conceived for cargo container monitoring is presented. Two piezoelectric transducers (PTs) operating at 40 kHz are fixed to the metallic wall by means of a customized magnetic case, allowing a noninvasive inside-outside communication preserving the container integrity. Once the resulting ultrasonic...