Abstract: An array microphone system includes a first omni-directional microphone, a second omni-directional microphone, a gain control, and a beam former. The first omni-directional microphone faces a first direction. The second omni-directional microphone faces a second direction opposing the first direction. When receiving sound, the first omni-directional microphone and the second omni-directional microphone respectively generate a first signal and a second signal. The gain control amplifies the second signal to transform into a third signal, wherein strength of the third signal is equal to that of the first signal when the sound comes from the first direction. The beam former separates an in-beam sound signal and an out-beam sound signal from the first signal and the third signal.

Abstract: An array microphone system includes a first omni-directional microphone, a second omni-directional microphone, a gain control, and a beam former. The first omni-directional microphone faces a first direction. The second omni-directional microphone faces a second direction opposing the first direction. When receiving sound, the first omni-directional microphone and the second omni-directional microphone respectively generate a first signal and a second signal. The gain control amplifies the second signal to transform into a third signal, wherein strength of the third signal is equal to that of the first signal when the sound comes from the first direction. The beam former separates an in-beam sound signal and an out-beam sound signal from the first signal and the third signal.

Abstract: A communication device includes a Bluetooth module, an audio interface, a FM/AM radio wave module, and a microphone. The Bluetooth module receives a first audio signal. The audio interface receives a second audio signal. The first audio signal and the second audio signal are selectively sent out through the FM/AM radio wave module. The microphone receives a third audio signal which is selectively sent out through either the Bluetooth module or the audio interface.

Abstract: An electronic device includes a housing, a circuit board, and a microphone array. A plurality of acoustic openings is defined in the housing. The circuit board is placed in the housing. The microphone array is placed on the circuit board for receiving external sound via the acoustic openings in the housing.

Abstract: An electronic device includes a case, a sound absorbing tunnel, and a uni-directional microphone. The case defines a front acoustic opening and a rear acoustic opening. The sound absorbing tunnel is disposed in the case. The uni-directional microphone is disposed in the case, including a front to receive external sound via the front acoustic opening, and a rear to receive the external sound via the rear acoustic opening and the sound absorbing tunnel.