Abstract: Radio link coverage mapping systems and related techniques are provided to improve the operation of unmanned mobile sensor or survey platforms. A radio or communication link coverage mapping system includes a logic device configured to communicate with a communication module and a position sensor coupled to a mobile platform, where the communication module is configured to establish a wireless communication link with a base station associated with the mobile platform and the position sensor is configured to provide a position of the mobile platform as it maneuvers within a survey area. The logic device determines communication link quality data associated with the wireless communication link as the mobile platform maneuvers within the survey area, receives corresponding position data, and generates corresponding communication coverage information, which may be used to generate a radio link coverage map.

Abstract: The present invention relates to a rotor assembly where associated electric motors are configured to rotate the rotor, control the collective pitch of the rotor/assembly, and/or control the cyclic pitch of the rotor/assembly, by varying the relative rotational angle between two or more of the associated electric motors.

Abstract: Radio link coverage mapping systems and related techniques are provided to improve the operation of unmanned mobile sensor or survey platforms. A radio or communication link coverage mapping system includes a logic device configured to communicate with a communication module and a position sensor coupled to a mobile platform, where the communication module is configured to establish a wireless communication link with a base station associated with the mobile platform and the position sensor is configured to provide a position of the mobile platform as it maneuvers within a survey area. The logic device determines communication link quality data associated with the wireless communication link as the mobile platform maneuvers within the survey area, receives corresponding position data, and generates corresponding communication coverage information, which may be used to generate a radio link coverage map.

Abstract: The present invention relates to a rotor assembly where associated electric motors are configured to rotate the rotor, control the collective pitch of the rotor/assembly, and/or control the cyclic pitch of the rotor/assembly, by varying the relative rotational angle between two or more of the associated electric motors.

Abstract: A method for reducing keyboard noise in conferencing equipment which includes a microphone and a keyboard, the method including: providing, at a noise reduction apparatus, an audio signal originating from the microphone; detecting, at the noise reduction apparatus, an operation of the keyboard; providing, at the noise reduction apparatus, a pre-stored estimate of a keyboard audio noise resulting from the operation of the keyboard upon detection of the operation of the keyboard; and calculating, at the noise reduction apparatus, a noise reduced output signal based on the estimate of the keyboard audio noise and the audio signal.

Abstract: A method for reducing keyboard noise in conferencing equipment which includes a microphone and a keyboard, the method including: providing, at a noise reduction apparatus, an audio signal originating from the microphone; detecting, at the noise reduction apparatus, an operation of the keyboard; providing, at the noise reduction apparatus, a pre-stored estimate of a keyboard audio noise resulting from the operation of the keyboard upon detection of the operation of the keyboard; and calculating, at the noise reduction apparatus, a noise reduced output signal based on the estimate of the keyboard audio noise and the audio signal.

Abstract: A communication system for transferring audio signals includes an audio presenting unit configured to produce a sound wave, an audio capturing unit configured to capture a sound wave, and an acoustic echo canceller unit connected to the audio presenting unit and the audio capturing unit. The audio echo canceller unit includes a model of an acoustic wave, in which the model produces an echo estimate which is subtracted from the captured sound wave which includes an echo, and the audio presenting unit includes a sound producing device connected and controlled by a current controlled source. The communication system further includes a compensator configured to provide an electrical damping for the sound producing device. Alternatively, the sound producing device is connected and controlled by a weighted combination of voltage and current controlled source.