Simrad Simrad SP70, Installation Manual

Page: 165 / 230

Final tests and measurements
149
851-164336 / D
8 Enter the measured hydrophone voltage U(p-p) into the
Measurement and calculation results table, and calculate the
U Hydr voltage in the same table.
→
Refer to table 6.
Measurements/calculations Value Unit Example
Noise level dB --25.2
Hydrophone voltage U(p--p) volt 0.8
U(RMS) = U(p--p)/2
√
2 volt 0.28
U Hydr = 20 log U(RMS) dB//1V --10.9
Table 6 Measurement and calculation results
9 Make the requisite calculations in the Measurement and
calculation results table, and enter the result into the
Receiving voltage response (VR) table.
→
The Receiving voltage response (VR) table is shown as
table 7.
10 Retrieve the Hydrophone sensitivity as transmitter S from
the Test hydrophone data table.
→ The Test hydrophone data table is shown as table 3 on page
144 (Source level measurements).
11 Enter the data into the Receiving voltage response (VR)
table.
12 Retrieve the 20 log r value from the Measurements results
table.
→
The Measurements results table is shown as table 4 on page
146 (Source level measurements).
13 Enter the data into the Receiving voltage response (VR)
table.
VR =
÷
(S + U Hydr
÷
20 log r)
Data Value Unit Example
S = S Hydrophone
dB// µ Pa /V
119.2
U Hydrophone dB//1V --10.9
20 log r dB 17.5
VR (Voltage Response)
dB//1V/
µ
Pa
--90.8
Table 7 Receiving voltage response (VR)
14 Calculate the voltage response with the formula given in
Receiving voltage response (VR) table.
Expected receiving voltage response is approximately:
•
VR = -90
±
3 dB//1V/
µ
Pa