The following is for BBS distribution. More information is available
from John Rice via AV-SYNC BBS (404) 320-6202 or phone (404) 451-8438.
TELECAST ENCRYPTION
TECHNICAL SPECIFICATIONS
The Telecast System is divided into (3) three groups, the
Computer, Encoder and Decoder. The system offers a very secure
signal by randomly time shifting the audio and randomly inverting
the video. The randomness is designated by setting a pattern to
follow. The system computer is used to enter the proper authorization
codes for events to be shown.
The Encoder generates a signal for authorization of the
selected decoders, sent to the decoders before the main program
is transmitted. Signal includes the Decoder Address, Key Codes,
Service Codes and Program Codes; it is sent in the clear and
looks like bar codes when viewed on television. The Encoder
then encrypts both audio and video signals for uplink
distribution. The Decoder decodes the information and processes
the main program to separate audio and video outputs.
The Encoder is divided into (2) two groups, the Scramble
System and the Address Insertion System. The Scramble System
contains the Audio Scramble Unit, Video Scramble Unit and Code
Processor Unit. The Address Insertion System is comprised of
the Address Insertion Unit, Address Data Control Unit and
Communication Interface Unit.
Both the audio and video are converted from analog to digital
for scrambling and then returned to analog for distribution.
The Encoder employs compensation and noise suppression circuits
to prevent any transient spikes that may occur during the
scrambling process.
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GENERAL SPECIFICATIONS
SCRAMBLE METHOD
VIDEO : Random polarity inversion
AUDIO : Random time shift
SUBSCRIBER ADDRESSING
MAXIMUM ADDRESS : 1,219,584 Per Address Insertion System
ADDRESS TIME : MINIMUM = 35 seconds to address 101,632
MAXIMUM = 6.5 min. to address 1,219,584
VIDEO SCRAMBLING UNIT
SIGNAL SYSTEM : NTSC TV standard
SCRAMBLE METHOD : Video polarity inversion
SCRAMBLE TIMING : Scene change or image movement
VIDEO INPUT : NTSC composite video, negative sync; the
level = 1.0 Vp-p + or - 3db adjustable
VIDEO OUTPUT : 0.822 Vp-p + or - 3db adjustable (75 IRE)
Composite video, negative sync @ 75 Ohms
BAND WIDTH : + or - 0.3db to 4.2 Mhz
SIGNAL TO NOISE : 55db (UNWEIGHTED)
DG : 2%
DP : 2 degree
COMMAND CODE and
PEDESTAL REFERENCE
PULSE LEVEL : 75 IRE
INVERSION AXIS : 41.25 IRE
SETUP LEVEL : 7.5 IRE
AUDIO SCRAMBLING UNIT
SCRAMBLE METHOD : Random time shift
RESOLUTION : 16 bits linear
FREQUENCY RESPONSE : +0.5, -1.0db at 30 to 15Khz
DYNAMIC RANGE : More than 90db
AUDIO LEVEL ---
LINE IN : +2, +8dbm (selectable)
LINE OUT : +2, +8dbm (selectable)
MONITOR OUT : -5db
IMPEDANCE ---
LINE IN : 10k, 600, 150 Ohms (selectable)
LINE OUT : 600, 150, 37.52 Ohm (selectable)
MONITOR OUT : 600 Ohms
FLICKER TEST : ON/OFF
SCENE CHANGE : Detector has 8 selectable modes
START CUE : Delay adjust = 0 - 9 seconds
PRINTER OUTPUT : Equivalent to Centronix Interface
Factory recommendation is SONY SMI-7020
ADDRESS DATA CONTROL UNIT
MEMORY CAPACITY : 1,219,584 bits
ENCRYPTION TIME : Approximately 100,000 bits/minute
COMMUNICATION INTERFACE UNIT
MEMORY CAPACITY : 1,219,584 bits
COMMUNICATION ---
PORT : EIA RS-232C
PROTOCOL : IBM 3780 BSC transparent
TIME : Host Computer to Inserter ----
20 seconds for 101,632 bits @ 9600 baud
The following is for BBS distribution. More information is available
from John Rice via AV-SYNC BBS (404) 320-6202 or phone (404) 451-8438.6-8044 1200 N81N V Illumi-Net 377-1141 1200 N81N V INDEX System II 991-3569 1200 N81N V Information Shoppe 288-7535 1200 N81N V InSight 455-4707 1200 N81N V ISIS 446-6931 1200 N81N V ISOPIA 422-2250 1200 N81N Na IT BBS of Atlanta 471-8824 1200 N81N ++ JOBBS! 992-8937 1200 N81N ++ Jodeco House 478-7761 1200 N81N V KASPER'S TI 939-0526 1200 N81N V Labyrinth ST (ESTSA) 594-0700 1200 N81N V Lair 995-0847 1200 N81N V LARC