Abstract:
A housing having a port for reducing wind-induced noise in a communication device. The housing includes a first channel, a second channel, and a ridge between the first and second channels. The housing further includes a tunnel extending through the ridge, which tunnel connects the first and second channels. The housing further includes a microphone port beneath the ridge, which microphone port is connected to the tunnel and connects the tunnel to a microphone cavity in the housing.
Abstract:
An intrinsically safe audio circuit and intrinsically safe portable two-way radio device meet conventional audio output requirements and intrinsically safe design limitations by separating the speaker coil of the device's speaker into separate coils to limit the energy storage possible in any one of the coils. Each separate coil is driven by one of several different audio power amplifiers that each output a substantially identical signal, and each of which are current limited.