BENTHOWAVE INSTRUMENT INC. Acoustic Transducer & System
BII's continuous/discrete line array hydrophones are designed for use in
detection and search of sound sources underwater, passive SONAR,
listening systems, near-field measurement and calibration.
BII-7021 and BII-7021Q are discrete linear array to support Digital
or FFT Beamforming, and can be used as broadside
and endfire array. The narrow beamwidth along the
length provide direction information of the sound sources and reject the unwanted
noises coming from other directions; the
omnidirectional response cross the length covers large area to
search. Two or four line arrays can be used to set up "T" or "+"
type cross array functioning as a Target Angle
Estimation System with Mills Cross techniques which provides accurate bearing information of
sound sources.
BII-7022 averages sound pressures along the Line Array, and
support built-in amplitude shading/weighting.
BII-7023 integrates the sound pressures along its
surface and support amplitude shading/weighting. The integration of the sound pressures along a line can be
used in measurement of acoustic radiation field, trouble-shooting,
maintenance and development of transducers and arrays, and
researches in theoretical acoustics such as boundary element
acoustics, Green's function, Helmholtz integral and Rayleigh's
integral, etc...
The body of BII-7020 series is streamlined hemispherical domes which
minimize the drag forces and the hydrodynamic noise caused by the
hydrophone in motion or the flow past the hydrophone.
For the array less than 15kHz, please refer to
BII-7010 hydrophone or
BII-7140 Hydrophone to set up discrete array.
Suggested Application | |
Towed Array, Sonobuoy, PAM System Tracking of Acoustic Tags Direction-finding Sonar System Target Angle Estimation Systems Locating Marker/Pinger/Beacon/Transponder |
Near-field Calibration and Measurement Hydrophone Calibration Trouble-shooting, Maintenance and Development of Transducers and Arrays Acoustic Pipeline Leak Detection Directional Communication |
Related Products | |
BII-7010 hydrophone Low Noise Broadband Hydrophone | BII-7140 Hydrophone Acoustic Element for Array/Streamer/Beacon |
Specification
Sensitivity Loss over Extension Cable (dB) = 20*log[Ch/(Ch+Cc)]. Ch: Hydrophone Capacitance; Cc: Capacitance of Extension Cable. Cable is of 100pF/meter roughly. Valid for hydrophone without preamplifier. |
Line Array Hydrophone | BII-7021Q | BII-7021 | BII-7022 | BII-7023 |
Signal Processing: | None | None | Averaging of Sounds | Integration of Sounds |
Operating Frequency: | 1Hz to 10 kHz | 1Hz to 25 kHz | 1Hz to 160 kHz | 1Hz to 160 kHz |
Array Element Quantity: | Discrete, N; N ≤ 32. | Discrete, N; N ≤ 32. | Continuous | Continuous |
Signal Output: | N | N | 1 | 1 |
Element Spacing d: | ≤ λ/2, Bespoke. | ≤ λ/2, Bespoke. | 0 mm | 0 mm |
Acoustic Aperture: | Φ31.8xL (mm): L=(N-1)*d | Φ24xL (mm): L=(N-1)*d | Φ9.5xL (mm) | Φ9.5xL (mm) |
Beam Pattern: | Toroidal Shape | Toroidal Shape | Toroidal Shape | Toroidal Shape |
Beam Steering: | Electronic or Software | Electronic | Mechanical or Manual | Mechanical or Manual |
Along-length Beam Width: |
No Shading: 2*arcsin(1.4*λ/(PI*L)) |
No Shading: 2*arcsin(1.4*λ/(PI*L)) |
No Shading: 76200°*kHz*mm/(f*L) |
No Shading: 76200°*kHz*mm/(f*L) |
Cross-length Beam Width: | Omnidirectional | Omnidirectional | Omnidirectional | Omnidirectional |
Voltage Sensitivity: (Without Shading) |
-189.4 dB V/μPa | -191.5 dB V/μPa | -200.0 dB V/μPa | -200.0 dB V/μPa |
Output Type: | Differential | Differential | Differential | Differential |
Element Capacitance: | 2.6nF | 3.7nF | 0.225nF/mm*L | 14.4nF*mm/L |
Diameter ΦD: | Φ42mm | Φ33mm | Φ21mm | Φ21mm |
Length (mm): | L+20 | L+20 | L+20 | L+20 |
Cable: | Shielded Cable Bundles, Twisted Pairs. |
Shielded Cable Bundles, Twisted Pairs. |
Shielded Cable, Twisted Pair. |
Shielded Cable, Twisted Pair. |
Transmitting Sound: | No | No | No | No |
Maximum Array Length: | Maximum array length BII can manufacture is 1.5m. |
Shading/Weighting: | 1. Default: No (Blank) 2. Dolph-Chebyshev (DC) 3. Binominal (BN) |
Side Lobes: | 1. No Shading: ≤-13.4 dB; 2. Dolph-Chebyshev: ≤-40.0 dB; 3. Binominal: No Side Lobe. |
Receiving face: | Cylinder |
Signal Conditioning: |
Hydrophone Preamplifiers Not included, order
separately. Signal Filter Not included, order separately. |
Operating Depth: | 300m, Maximum |
Information: | Acoustic Components and System: Installation/Mounting, Ordering, Wiring, Array & Aperture Design and much more. |
Technical note: for long line array, to avoid high pull force acting on the underwater connectors and the array cables, a reinforced rope with high pull strength shall be used along the array, and the array cables are tied on the reinforced rope with soft cotton rope (avoid scratching or damaging cable jacket). Make sure that ONLY reinforced rope withstands high pulling force during field operation. BII does not sell reinforced rope and soft cotton rope, which are usually available at buyer's local stores. |