Microphone arrays and communication systems for directional reception

A method of directional signal reception, comprising:

• using first and second microphones, fixed to a substrate, as an end-fire array to detect sound from a left rear region of an area;
• using the first microphone and a third microphone as an end-fire array to detect sound from a right rear region of the area, wherein the third microphone is fixed to the substrate;
• using the second microphone and a fourth microphone as an end-fire array to detect sound from a first front region of the area, wherein the fourth microphone is fixed to the substrate;
• and
• using the third microphone and the fourth microphone as an end-fire array to detect sound from a second front region of the area, different from the first front region of the area;
• wherein the four microphones are arranged such that mathematical projections of the first, second, and third microphones in a plane provide corners of a triangle in the plane, mathematical projection of the fourth microphone in the plane is disposed in an interior of the triangle, at least one of the four microphones is disposed at a first distance from the plane, another of the four microphones is disposed at a second distance from the plane, and the first distance is different from the second distance.

A four-microphone array for directional signal reception, comprising:

• first, second, and third microphones arranged such that mathematical projections of the first, second, and third microphones in a plane provide corners of a triangle in the plane;
• and
• a fourth microphone arranged such that a mathematical projection of the fourth microphone in the plane is disposed in an interior of the triangle;
• wherein a distance between the first microphone and the second microphone is different from a distance between the first microphone and the third microphone.

A four-microphone array for directional signal reception, comprising:

• first, second, and third microphones arranged such that mathematical projections of the first, second, and third microphones in a plane provide corners of a triangle in the plane;
• and
• a fourth microphone arranged such that a mathematical projection of the fourth microphone in the plane is disposed in an interior of the triangle;
• wherein at least one of the four microphones is communicatively coupled to a communications device, the communications device is coupled to a two-wire bus, and the communications device is in communication with at least one upstream device over the two-wire bus;
• and
• wherein the communications device includes:
• upstream transceiver circuitry to receive a first signal transmitted over the two-wire bus from an upstream device and to provide a second signal over the two-wire bus to the upstream device;
• downstream transceiver circuitry to provide a third signal downstream over the two-wire bus toward a downstream device and to receive a fourth signal over the two-wire bus from the downstream device;
• and
• clock circuitry to generate a clock signal at the communications device based on the first signal, wherein timing of receipt and provision of signals over the two-wire bus by the communications device is based on the clock signal.