Benthowave Instrument Inc.

BENTHOWAVE INSTRUMENT INC. Acoustic Transducer & System 

Parametric Array Transducer: Sediment Profiling

parametric arrayParametric TransducerParametric Transducerparametric array

BII-7540 Parametric Array Transducer: Sediment Profiling

Benthowave's underwater parametric Array transducers are designed for uses in sub-bottom profiling, and are optimized to explore the first layers of sediment below the sea floor. BII-7540 series parametric array features narrow directivity pattern at the low frequency and seafloor penetration of tens of meters. To achieve a deference frequency, BII-7540 series transducers need two signal sources as inputs: Low frequency primary signal source and high frequency primary signal source.

To meet the flexible design demands of parametric array, BII manufactures array elements (BII-7546 and BII-7547) which are suitable to be integrated into a reconfigurable parametric array achieving high source level, deep penetration of sediments and specific beamwidth. For example, you may assemble a 0.5m x 0.5m square parametric array with multiple BII-7546s and BII-7547s to achieve 3.5kHz narrow-beam sound, which can penetrate sediments deeper than 10 to 50 meters. After current field project is done, these array elements can be assembled into different array patterns in next project. Besides, BII-7546 and BII-7547 can be used individually for other underwater applications such as communication, echosounding, beaconing, directional hydrophone, etc...

Technical Note:
When two underwater sound waves of different primary frequencies fp1 and fp2 (fp1>fp2) propagate in the same direction, they interact with each other to create low frequency sound wave of secondary frequency fs (fs=fp1-fp2). This difference frequency sound is useful for practical applications in sediment profiling, depth sounding and communication.
Attenuation/absorption coefficient of sediments is frequency dependent around 0.06f to 0.6f (dB/(m*kHz)).
Parametric array gain or efficiency is better as primary sound powers are higher, secondary frequency fs is higher, down shift ratio (fp1+fp2)/(2fs) is lower, and (αp*Rr) is lower (αp: mean primary sound attenuation coefficient; Rr: rayleigh distance).

Suggested Application  
Sub-Bottom Investigation/Assessment/Profiler
Sediment Profiling/Sediment Penetrating
Detection of Buried Objects
Search Pipeline/Cable Survey
R & D on Nonlinear Underwater Acoustics
Low Frequency Narrow Beam Sound Sources
Features  
High Spatial Resolution
Support Broadband Signals
Low Frequency Generation: Flexible & Reusable
High Penetration Capability
Easy Mounting/Installation/Deployment
Light Weight (Comparing to Tonpilz Transducers)
Related Products  
BII-2030 Envelope Detection
BII-5000 Power Amplifier
BII-6000 Impedance Matching & Tuning Unit
BII-8030 Underwater Acoustic Transmitter
BII-8080 Transmitting and Receiving System
Sonar Signal Generation

Specification

Parametric
Transducer
Pulsed
Signal
Primary
Frequency
(kHz)
Secondary
Frequency
(kHz)
Source
Level (10kHz)
Penetration
Capability
-3dB Beam
Width
TVR
dB μPa/V@1m
OCV
dB V/µPa
Size
ΦDxH mm
Weight
(kg)
BII-7541 Ricker, CW, Chirp/FM 180 to 210 2 to 20 >203 dB µPa@1m >40 m N/A -185 114x50 1.0
BII-7542 CW 180 to 210 2 to 20 >199 dB µPa@1m >20 m N/A -195 89x50 0.7
BII-7543 Ricker, CW, Chirp/FM 100 to 130 2 to 20 >203 dB µPa@1m >40 m N/A -192 168x50 5
BII-7544 Ricker, CW, Chirp/FM 50 to 80 2 to 20 >203 dB µPa@1m >40 m 11º N/A -191 168x50 5.6
BII-7546 Ricker, CW, Chirp/FM 25 to 35 1 to 10 N/A N/A 80º 141 -174 48x60 0.6
BII-7547 Ricker, CW, Chirp/FM 30 to 40 1 to 10 N/A N/A 75º 142 -174 48x60 0.6
Note: 1. Transducer Weight is measured in air with two 1m cables. Generally, cable weight is 0.066 kg/m.
2. Both
BII-7546 and BII-7547 are array elements for a reconfigurable parametric array to achieve low secondary frequency. More transducers for use in sediment profiling: BII-7500 High Power Broadband Piston Transducer.
Radiation Face: Circular Plane
Drive Voltage: 600Vrms Maximum.
Duty Cycle: 1% at 600Vrms.
Temperature Sensor: 1. Default: No built-in temperature sensor.
2. Built-in temperature sensor. When ordering, append TS to part number for integrating a temperature sensor in the transducer. Click Temperature Characteristics for more information.
Depth Rating: 300m
Impedance Matching: Custom BII-6000: 4 to 16Ω, 50Ω, 60Ω, 100Ω,...; Not included, order separately, Append IM to part number
T/R Switch: BII-2100 Transmitting & Receiving Switch; Not Included. Order Separately, Append TR to part number.
Mounting Options: 1. Default: Free Hanging (FH)
2. Free-hanging with Two Male Underwater Connectors (FHUWC)

3. Thru-hole Mounting with Single O-ring (THSO)
4. Thru-hole Mounting with Double O-ring (THDO)
5. Bolt Fastening Mounting (Stainless Steel): (BFMSS)
6. End-face Mounting:  (EFM)
7. Flange Mounting: (FGM)
Click
Transducer and Hydrophone Mounting for more detailed information on mounting/installation.
Cable Length: 1. Default: 1m
2. Custom
Cable: 1. Shielded Cable (SC)
2. Wire/Cable Bundle (WCB): ONLY for Thru-hole Mounting
Connector: 1. Default: Wire Leads (WL)
2. Underwater Mateable Connector (UMC)
3. MIL-5015 Style (5015)
4. Custom (custom)
Operating Temperature: -10°C to +60°C
Storage Temperature: -40°C to +60°C
How to Order: Click How to Order.

Transducer Wiring

Two Shielded Cables (Free Hanging and Flange Mounting) Signal
Red or White Wire of Cable label “0” Primary High Frequency Signal +
Black Wire of Cable label “0” Primary High Frequency Signal -
Shield of Cable label “0” System Grounding for Safety
Red or White Wire of Cable label “1” Primary Low Frequency Signal +
Black Wire of Cable label “1” Primary Low Frequency Signal -
Shield of Cable label “1” System Grounding for Safety
   
Two Free Hanging with Underwater Connector (FHUWC) Signal
Pin 1 of Underwater Connector at Off-Center Primary High Frequency Signal -
Pin 2 of Underwater Connector at Off-Center Primary High Frequency Signal +
Pin 3 of Underwater Connector at Off-Center System Grounding for Safety
Pin 1 of Underwater Connector at Center Primary Low Frequency Signal -
Pin 2 of Underwater Connector at Center Primary Low Frequency Signal +
Pin 3 of Underwater Connector at Center System Grounding for Safety
   
Wire/Cable Bundle (Thru-hole and End-face Mounting) Signal
Red Wire Primary High Frequency Signal +
Black Wire Primary High Frequency Signal -
White Wire Primary Low Frequency Signal +
Green Wire Primary Low Frequency Signal -
   
Shielded Cable  (Bolt Fastening Mounting) Signal
Red Wire Primary High Frequency Signal +
Black Wire Primary High Frequency Signal -
White Wire Primary Low Frequency Signal +
Green Wire Primary Low Frequency Signal -
Shield System Grounding for Safety
   
Beam Pattern of Parametric Transducer Driving Signals (Free Hanging & Flange Mount)
Parametric Transducer Parametric Array

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