The working principle of MDPB-L7S is to emit ultrasonic waves with random noise that cannot be perceived by human ears. When digital devices such as mobile phones record, these noises are recorded together with the sound of normal conversation into the digital device, making the recorded audio invalid. The audio information in the recorded video also has the same interference effect. Since the noise with ultrasonic noise is generated randomly and cannot be restored, the audio after interference can not be restored, so as to ensure that the original information is not leaked and transmitted.

Good anti-recording effect: our self-developed FPGA-based ultrasonic noise algorithm can effectively interfere with mobile phones, recording pens and other digital equipment, the anti-recording effect is at an advanced level, and can effectively ensure that the conversation is not recorded, so as to ensure the security of information;

Large scope: the protection range of a single anti-recording device is approximately a conical space, the interference range is about 15 square meters, and the interference distance of most mobile phones and other digital products is more than 2 meters, which can form a safe space, and there is no need to worry about being recorded by others in this space;

Many devices: We have tested iPhone, Huawei, Xiaomi, OPPO, VIVO, Samsung, Nubia, Meizu, Guan and other new and old models of mobile phones, the interference effect is good, the test SONY, Samsung, Newman, Lenovo, Olympus and other recorders, the interference effect is good;

Quiet guardian: The sound waves issued by the anti-recording device are only received by mobile phones, recording pens and other digital products, but the sound that people can not hear is not buzzing noise compared with other anti-recording devices, and the quiet guardian conversation environment is not easy to be detected.