Tvg Level; Echo Offset - Furuno FE-700 Operator's Manual

4.3 TVG Level

TVG (Time Varied Gain) compensates for
propagation attenuation of the ultrasonic waves,
reducing surface noise to provide a smooth
display. The TVG lowers receiver sensitivity at
the time of pulse emission and gradually
increases it with time, thereby making objects of
same reflectivity at different depths appear at the
same intensity or colors on the display. The TVG
working depth is down to approximately 150 m
on the 200 kHz system and 350 m on the 50 kHz
system. Outside this range the echoes from the
seabed and fish schools are received in full level.
There is no perceivable deterioration in
performance.
1. Press the DRAFT key three times at the
EXTENSION MODE display. The TVG
SELECT window appears.
TVG SELECT
200kHz =
-+: 200kHz
2. Set the TVG curve with [+] or [-]. The default
level is 5. Attenuation compensation curve is
at 20LogR curve.
3. Press the POWER switch to finish the
adjustment. Wait 5 s, and then turn it on
again.
Note: Do not switch transducer (frequency) at
the EX-8 when setting the TVG Level menu. If it
is necessary to set TVG level for a different
frequency, turn off the FE-700, switch transducer
at EX-8 and then turn on the FE-700 again.
5 (0∼9)

4.4 Echo Offset

The echo offset feature functions to compensate
for too weak or too strong echo level. If the on-
screen echo level appears to be too weak or too
strong and the level cannot be adjusted
satisfactorily with the GAIN control, do the
following to adjust echo level.
1. Press the DIM key three times at the
EXTENSION MODE display. The ECHO
OFFSET screen appears.
ECHO OFFSET
200kHz:
-+: 200kHz
2. Set the offset with [+] or [-]. The default
value is 0.
3. Press the POWER switch to finish the
adjustment. Wait about 5 s and then turn it
on again.
15
0 (-99∼+99)