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500, series portable.
echo ,sounders
2 TECaN:r(~AL
DESCRIPTION
INTRODUCTION
The transceiver unit contains the following printed circuit boards/modules:
* PC Interface board
* Digital transceiver board
* Analog transceiver board
, single beam or split beam
* Backplane
* Power module
Figure 4 shows a simplified block diagram of the transceiver.
DISPLAY
HARDDISK
KEYBOARD
CLOCK
COM 1
COM 2
TRANS- ~
DUCER
ANALOG
TRANSCEIVER
AMPL.
PHASE
DIGITAL
TRANSCEIVER
m""""""""",,"','.',$,'.';."-
""',$';.~~""""',m,'
INTERFACE
"'~:'2;
2;;
1::
:::i::-
PRINTER
(CD478)
2xFO
Figure 4
Transceiver block diagram.
* The
analog transceiver/digital
transceiver combination contains transmitter
receiver and
AID-conversion circuitry. The receiver does not contain any
TVG (Time Varying Gain) function as the echo sounder implements this
function solely in software. Instead , the receiving system is designed as a
power meter
with a large instantaneous dynamic range. Input power levels
from -
160 dBW
to
0 dBW (dB'
s relative 1
W) are measured
to
a precision of
a fraction of a dB and are output
to
the PC interface board as 16-
bit digital
words using the dBW scale for numeric representation. The receiver includes
one receiving channel for single beam operation. For split-
beam operation
the
receiver includes four matched
channels plus phase
measurement
circui try.
P3405E/B
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