LDI DIGISONDE 4D - Digital Transmitter Card; Functional Description

LDI Intellectual Property.
Not for secondary distribution or replication, in part or entirety.
DIGISONDE-4D
SYSTEM MANUAL
VERSION 1.2.11
4-8 SECTION 4 – HARDWARE DESCRIPTION
xii. ISA and PCI Interface via backplane
e. The Power Distribution board converts the 24 to 28 V DC primary power to the +15, –15, +12,
+5, +3.3, and –5 volts needed by various components in the system. The RF power amplifier
circuitry can utilize the 24 to 28 V DC directly.
f. Two x 150 W solid state RF power amplifiers operating over a range of 1 MHz to 30 MHz.
g. Electronically switchable right or left hand circularly polarized active receiving antennas, pow-
ered and controlled by the Antenna Switch.
4:3. The Digisonde-4D hardware has been designed not only to replace the analog RF circuitry with their
digital counterparts, but also to rework configuration of the embedded computers and corresponding data
interfaces. As new powerful embedded computers and fast interface solutions have become available, it is
now feasible to capture the complete set of raw data for processing in the computer by implementing data
processing functions in software.
4:4. All relevant computations in the Digisonde-4D are managed by two embedded computer platforms.
The Control Platform provides low-level hardware control and data acquisition functions and the Data Plat-
form processes the raw sample data. Processing in the Data Platform is done independently of the time-
deterministic processes involved in controlling the measurements, thus permitting cleaner structuring of the
real-time operations and their implementation as separate, well defined tasks under management of the
RTOS.
CHAPTER 2
PROPRIETARY CIRCUIT BOARDS
DIGITAL TRANSMITTER CARD
4:5. The transmitter specifications are given in Table 4-1.
Table 4-1: Transmitter Specifications
Function
Value
Note
Output frequency
0.1 MHz to 30 MHz
Programmable, 32-bit precision
Output voltage in transmission mode
0.5 V
p-p
to 1.5 V
p-p
Output voltage in inter-channel calibration
45 mV
p-p
or 1 V
p-p
Size
4” ½ X 5”
Control interface
Parallel Port
EPP mode, 3.3 V
Supply voltages
+/- 5, +/- 15, +3.3 V
Functional Description
4:6. Figure 4-5 shows the functional block diagram of the Digital Transmitter. Like its predecessor the
DPS4, the DPS4D uses two transmitter channels to form left or right-hand polarized signals by driving two