Evaluation of a Speech Jammer Prototype Using Ultrasonic Signals
Kazuhiro Kondo, Hayato Yamada, Noriyuki Hayasaka · 2024
We evaluated the speech jamming capability of a jammer prototype using ultrasonic signals. The prototype outputs a modulated ultrasonic signal to jam the recording of conversational speech on a hidden recording device. The ultrasonic signal is demodulated as noise at the recorder due to the nonlinearity of the analog front-end circuitry of the device but is inaudible to the human ear. The prototype reduced the intelligibility of recorded speech to well below 20% in all directions surrounding the prototype, proving its effectiveness as a jammer.