Calibration Sphere Settings dialog box

The Calibration Sphere Settings dialog box allows you to specify the sphere TS frequency response and exclusion zones (where calculations are undefined).

To open the Calibration Sphere dialog box, click Edit... on the Sphere Settings tab of the Calibration Assistant.

TS Distribution

The TS Distribution section is used to specify the calibration sphere TS frequency response.

Select a Sphere TS model from the list of modeling methods:

Calculated from sphere parameters
Single TS value
TS frequency distribution

Calculated from sphere parameters

Setting	Description
Sphere material	The Sphere material list includes: Tungsten carbide Default values are applied for Sphere density (kg/m3), internal Longitudinal sound speed (m/s) and internal Transverse sound speed (m/s). Copper Default values are applied for Sphere density, internal Longitudinal sound speed (m/s) and internal Transverse sound speed (m/s). Aluminum Default values are applied for Sphere density, internal Longitudinal sound speed (m/s) and internal Transverse sound speed (m/s). Other Enter values for Sphere diameter (mm), Sphere density (kg/m3), internal Longitudinal sound speed (m/s) and internal Transverse sound speed (m/s). This section is particularly useful for the case where the nominal internal Longitudinal and internal Transverse sound speed are inaccurate. Demer et al (ICES CRR No. 336, 2017) observe that "If these values are inaccurate, the sphere TS(f) will not exactly match theory, most conspicuously at the locations of nulls and where the TS from multiple spheres overlap. ..."
Sphere diameter (mm)	Enter a value for sphere diameter.
Water density (kg/m3)	Enter a value for water density.

TS frequency response equation

The equations for calibration sphere TS frequency response are the same as those used by the Advanced Survey Technologies Southwest Fisheries Science Center. See also Calibration sphere modeling and references.

Single TS Value

Enter a TS (dB) value, for the Narrowband case.

TS frequency distribution

Paired TS (dB) and Frequency (kHz) values can be entered manually or use Paste to populate the TS Distribution table with tabulated data.

Exclusion Zones

Exclusion Zones specify frequency bands where the Calibration Assistant does not calculate output. Such frequency bands can bracket nulls in the sphere frequency response. Values may be entered manually or use Paste to populate the table with tabulated data. Valid range is 1 to 1000 kHz.