Patent ID: 11877117
Assignee: DRÄGERWERK AG & CO. KGAA
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H  A | IPC A  H

Claim 5:
6. A gas mask or helmet with a communication system, comprising:
a headset configured to output sound waves to an ear of a user based on an audio signal;
a first microphone configured to output a microphone signal based on ambient sound;
a processing circuit having an activation and a deactivation state, the activation state being configured to generate, based on the microphone signal, a signal component of the audio signal, the signal component having information about the generation of sound waves which interfere destructively with a component of the ambient sound occurring at the ear of the user, the deactivation state not generating the signal component; and
a control circuit configured to detect speech input signal components of the microphone signal which pertain to human speech of communicators who communicate with the user, and the control circuit is configured to generate a speech output signal component of the audio signal predominately based on the speech input signal components of the microphone signal, the control circuit filtering the speech input signal components, and amplifying the filtered speech input signal components via an automatic gain control, to generate the speech output signal, the control circuit configured to determine a loudness level of the ambient sound based on the microphone signal and to switch the processing circuit from the deactivation state to the activation state when the loudness level is above a reference level, the control circuit determines the reference level based on a loudness level measured by a second microphone on a side of the mask body facing the user.