Garmin GTN 725, Руководство по установке

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Page 4-22 GTN 725/750 TSO Installation Manual
Rev. A 190-01007-02
4.3.11.3 Heading Synchro Valid Input
Pin Name Connector Pin I/O
SYNCHRO VALID INPUT (ACTIVE HI) P1005 12 In
SYNCHRO VALID INPUT* P1005 33 In
P1005-12 is considered active if the voltage on this input is 6.5-33 VDC. If the voltage is ≤3.5 VDC, the
input is considered inactive.
P1005-33 is considered active if either the voltage to ground is <1.9 V or the resistance to ground
is <375
Ω
. This input is considered inactive if the voltage to ground is 11-33 VDC.
Unless P1005-12 or P1005-33 is active, the GTN will consider the synchro heading input to be invalid.
4.3.12 Composite Video (function not currently implemented)
Pin Name Connector Pin I/O
VIDEO INPUT 1 P1005 2 In
VIDEO INPUT 1 GND P1005 23 In
VIDEO INPUT 2 P1005 1 In
VIDEO INPUT 2 GND P1005 22 In
The GTN supports the following composite video input formats:
•
NTSC “National Television Standards Committee” (J,M,4.43)
•
PAL “Phase Alternating Line” (B,D,G,H,I,M,N,Nc,60)
•
SECAM “Sequential Color with Memory” (B,D,G,K,K1,L)
Composite video is a one-wire format with intensity, color, and timing information transferred together.
Video signals are transferred using a 75Ω coaxial cable. Reference
TBD for approved types of coaxial
cable.
NOTE
Particular attention must be taken in routing the coaxial cable through the aircraft to
avoid potential radiated interference sources in addition to minimizing the cable bend
radii. Concerns about interference sources may necessitate the use of coaxial cable with
a higher noise rejection rating.
NTSC (M), also called RS-170A, is the most common video format supported by the GTN.
NTSC has the following characteristics:
•
59.94 Hz vertical interlaced refresh rate
•
15.75 kHz horizontal line frequency
•
525 scan lines
•
29.97 frame per second update rate
•
Luminance or luma (black and white) also called “monochrome NTSC” or RS-170, is the
standard black and white format which contains both image and timing information.
•
Chrominance or chroma (color) encoding system