Simrad SP90 - REV E, Installation Manual

Page: 168 / 232

Simrad SP90
156
851-164510 / Rev.E
11.3 Receiving voltage response (VR)
Preparations
In order to measure the receiving voltage response, use the test
hydrophone in the same position as for the previous source level
measurements.
Use the following menu settings on the sonar.
1 Select the Setup menu.
2 Push the Test... button to access the System Test menu.
3 Push the Test Config button, and observe the Test Config
submenu appear at the bottom of the menu field.
4 Select Noise & VR to select the menu settings for the
receiving voltage response.
All the required sonar parameters for the voltage response
measurements have now been set automatically.
Procedure
Observe the following procedure to measure the receiving
voltage response. Note that the procedure calls for an
oscilloscope and a test oscillator.
1 Check that the bearing and tilt angle values are the same
as for the source level measurements.
→
Refer to table 4 on page 154.
2 Observe the Echo Level readout in the System test menu.
- This is the echo level which - without a signal
oscillator connected - is the noise level for the selected
bearing. The current value is shown on the
Echo level
button.
3 Enter the Echo level value into the cell for Noise level in
the Measurement and calculation results table.
→
Refer to table 6.
4 Connect a signal oscillator to the hydrophone.
5 Adjust the oscillator frequency to 26.0 kHz.
6 Connect the oscilloscope channel to measure the output
voltage to the hydrophone.
7 Adjust the oscillator voltage until the Echo level readout
is 0.0 dB.