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DIAGNOSTIC FUNCTION | Up
Fire Controlman Volume 05-Display Systems and Devices | Next
The functional block diagram of the basic display unit. |
Figure 4-14.—The basic display unit (BDU).
Symbol generator function
Conies generator function
Circular sweep control function
Analog deflection function
Intensity control function
Power distribution function
I N P U T / O U T P U T
FUNCTION.— The
input/output (I/O) function is the interface between
the basic display console and the BDU. The I/O
function has two subfunctional areas:
the input
subfunction and the output subfunction.
The input subfunction consists of digital and coax
line receivers. The receivers provide for impedance
matching and buffering of the input signals. The
input function also routes input data to other fictions
of the BDU.
The output subfunction of the BDU consists of
digital drivers to send symbol status signals back to
the display console.
SYMBOL GENERATOR FUNCTION.— The
symbol generator function contains the circuitry to
generate the symbology and alphanumerics for
display on the CRT. Symbols are generated using the
stroke method described in chapter 1 of this manual.
CONICS GENERATOR.— The conies generator
develops the signals required to display circles and
ellipses.
Circle radius can be from 16 to 1,023
deflection units in increments of 1 deflection unit.
The circle and ellipse data is received from the I/O
function. Size of the circle or ellipse is determined
and scaled to match the range setting of the display
console. Deflection voltages, consisting of sine and
cosine waveforms or conies radius, are sent to the
analog deflection control function.
CIRCULAR
SWEEP
CONTROL
FUNCTION.— The circular sweep control function
develops the signals required to display circular
sweep. The function receives the DC and DU pulse
4-13
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