DIRECTIONAL RECEPTION OF SOUND SIGNALS IN SOLID ANGLE Russian patent published in 2017 - IPC G01H11/00 

FIELD: physics.

SUBSTANCE: method of highly directional reception of sound signals in a solid angle not more than 15° is provided. 4 microphones are placed on a rigid linear rod. The microphones are used in pairs: one pair is located at the maximum distance L_max from each other, the other two pairs at the distances L_av and L_min, where L_max>L_av>L_min. Output signals from each pair of microphones are connected to three summing amplifiers through the low-frequency filters: at frequency F_res1 for a pair with the distance L_max, the mid-frequency filters on F_res2 with the distance L_av and the high-frequency ones on F_res3 with the distance L_min. Filter bandwidth relative to F_res1, F_res2 and F_res3 is ±(30÷40) Hz. Adjustable threshold devices are mounted at the output of the summing amplifiers, the output signals of which form a single output signal. Resonant frequencies F_res1, F_res2 and F_res3 are found from the expression , where S_s - the sound speed in air, L - the distance between a pair of microphones, α* - the angle of the sound wave arrival at the pair of microphones equal 35÷45°, wherein on F_res on the output summary amplifiers the output signal is zero.

EFFECT: improved reception.

2 tbl, 3 dwg