Development of a Programmable Ultrasonic Receiver

1. Development of a Programmable Ultrasonic Receiver Chris Allen (callen@eecs.ku.edu)

2. Outline • Ultrasonic signals • Ultrasonic receiver applications • Ultrasonic receiver requirements • Candidate component technologies

3. Ultrasonic signals • Inaudible to humans • Some animals and insects use ultrasonic signals for communication, navigation, hunting, etc. • Humans use ultrasonic signals for structures testing, medical applications (imaging, flow measurement), industrial processes, and ranging/communication Compared to the speed of light, the speed of sound is very slow (6 orders of magnitude lower) 1-cm EM wavelength  30 GHz in air 1-cm acoustic wavelength  33 kHz in air

4. Ultrasonic receiver applications • The availability of an ultrasonic receiver enables several applications • Ultrasonic radar system (when used with an ultrasonic transmitter) Applications include distance measurement, wind speed measurement, target detection / identification / tracking, ultrasonic imaging • Ultrasonic spectrum analyzer Applications include signal characterization/classification, propagation channel characterization, radiation pattern measurement, ambient noise measurement • Ultrasonic communications Applications include wireless signal distribution (non line-of-sight), covert communications, communication through structures (walls, floors, pipes) • Ultrasonic testing Non-destructive testing, industrial sensors

5. Ultrasonic receiver applications • The motivations for development of this programmable ultrasonic receiver include: • Development of an ultrasonic radar system Enables demonstration of various radar concepts for teaching/trainingProvides quick and low-cost evaluation of new radar concepts • Development of an ultrasonic spectrum analyzer Useful for system characterization and troubleshooting • Development of precision ultrasonic range measurement system Useful for avionics (formation flying UAVs) • Development of a wind speed measurement system To measure the vertical wind component near a wind turbine which may increase its conversion efficiency

6. Ultrasonic receiver requirements Operating frequency range 30 kHz to 50 kHz Signal bandwidth 1 kHz to 20 kHz Dynamic range 50 dB Number of channels 4 Output format USB interface Final assembly custom printed circuit board Size (max) 2.25” x 4” x 0.625” (10 cm x 5.5 cm x 1.5 cm)Weight (max) 80 gPower (max) 5 V @ 100 mA, 500 mW 6

7. Candidate component technologies Transducer Knowles SPU04010HR5H MEMS microphone 20 kHz to 80 kHz Amplifier Linear TechLT1208 hi-speed op amp 45 MHz bandwidth Linear Tech LTC6910 prog. gain amplifiers 11 MHz bandwidth Mixer Philips SA602A double-balanced mixer 500 MHz fmax Local oscillator Linear Tech LTC6903 programmable oscillator 1 kHz to 68 MHz input for external LO Processor Arduino Uno 8-bit microcontroller 5 V, 16 MHz Arduino Due 32-bit ARM microcontroller 3.3 V, 84 MHz 7

8. Candidate receiver circuit diagram(only one channel shown) 8

9. Ultrasonic Tx board already developed