DMC 254 Date: Apr 2014 Page: 1 Sync and Control Unit DMC 254 Rev B April 2014

DMC 254 Date: Apr 2014 Page: 1 Course Objectives Course description….. To understand the operation and management of the Video Synchronization & Control Units (SCUs) To provide detailed information on functions, interconnections to other elements of the onboard video systems, limitations and constraints, & high level commanding/routing.

DMC 254 Date: Apr 2014 Page: 1 Video Overview

DMC 254 Date: Apr 2014 Page: 1 SCU Overview Two SCUs are provided onboard. The Sync and Control Unit provides: –the means for camera commanding and status monitoring –synchronization of video cameras –split screen generation –time base correction –test signal generation

DMC 254 Date: Apr 2014 Page: 1 Video System Block Diagram Figure 1

DMC 254 Date: Apr 2014 Page: 1 SCU Overview The Time Base Correction (TBC) function of the SCU is provided to correct video signal jitter. Some video may require time base correction by the SCU. TBC functions can be performed by either the SCU providing the Master Black Burst Sync (BBS) signal or the other SCU. The Split Screen Processor (SSP) and TBC can be utilized on either SCU; but SSP and TBC can not be utilized simultaneously on an individual SCU. This is due to the video for both functions being routed to the same output on the SCU. Mission/Data Planners must take this constraint into account when scheduling TBC/SSP functions for the SCUs.

DMC 254 Date: Apr 2014 Page: 1 Video System Connection to SCUs Fixed SCU input and output provide interconnection to other video system components through the Video Switching Unit (VSU) Fig. 2

DMC 254 Date: Apr 2014 Page: 1 SCU to C & DH Data Connectivity SCU-1SCU-2 C&C MDM-1 CB CT-3 C&C MDM-3 C&C MDM-2 CB CT-4 CB CT-1 CB CT-2 Ku Comm Unit VSU-1VSU-2 VSU-3 CB CT-BIA-23 MIL-STD-1553B Fig. 2A VSU-5 VSU-4

DMC 254 Date: Apr 2014 Page: 1 Hardware Overview The SCU provides the primary BBS signal generation function for the ISS Video System. It provides the BBS signal to the VSUs. The VSUs have internal fiber optic repeaters to regenerate and distribute the master BBS signal to video sources. SCU 1 & SCU 2 has 4 video interfaces with VSU 1 and VSU 2, respectively, and provides BBS outputs for sync distribution to each of the VSUs. See Figure 1. The Video Interfaces for each SCU are provided in Table 1 & 2.

DMC 254 Date: Apr 2014 Page: 1 SCU to VSU Connectivity SCU Video System Interface VSU Interface SCU 1 Video A InputVSU 1 Output Port 1 SCU 1 Video B InputVSU 1 Output Port 2 SCU 1 FFTS OutputVSU 1 Input Port 1 SCU 1 Video OutputVSU 1 Input Port 2 SCU 1 Sync Output 1VSU 1 Sync A SCU 1 Sync Output 2VSU 2 Sync A SCU 1 Sync Output 3VSU 3 Sync A Table 1

DMC 254 Date: Apr 2014 Page: 1 SCU Video System Interface VSU Interface SCU 2 Video A InputVSU 2 Output Port 9 SCU 2 Video B InputVSU 2 Output Port 10 SCU 2 FFTS OutputVSU 2 Input Port 11 SCU 2 Video OutputVSU 2 Input Port 10 SCU 2 Sync Output 1VSU 1 Sync B SCU 2 Sync Output 2VSU 2 Sync B SCU 2 Sync Output 3VSU 3 Sync B SCU to VSU Connectivity Table 2

DMC 254 Date: Apr 2014 Page: 1 Hardware Overview Inputs/Outputs Four video interfaces are configured as 2 inputs and 2 outputs to/from a VSU. The SCU can also be configured to provide one of four Video test signals through a dedicated output to a VSU. These signals are used in alignment/troubleshooting of the Video Distribution System (VDS). The other output is used for Split Screen video distribution or output of Time Base Corrector (TBC) video. One of the two video inputs are used for TBC. The SSP function uses both video inputs. –It combines the two video signals into one composite video output.

DMC 254 Date: Apr 2014 Page: 1 Hardware Overview Split Screen/TBC The Split Screen display consists of the middle 50% of the video signal received on the Video A input (displayed on the left side of the screen) and the middle 50% of the video signal on the Video B input (displayed on the right side of the screen). Additionally, Video B is synched to Video A. TBC is performed on the recorded video signal received through the SCU’s Video B input. The SCU may be configured to TBC a video signal. The SSP function and the TBC function can not be active at the same time. However, SSP or TBC can be active while the Signal Generator is active. Also, all of these functions can all be disabled under the Normal Operations Mode (State No. 6).

DMC 254 Date: Apr 2014 Page: 1

Hardware Overview Vertical Interval External Camera commands distributed through the 1553 interface are encoded on the BBS signal. Vertical Interval Lines contain the camera command information. This information is provided on all 5 BBS outputs from the SCU providing the Master BBS signal. Vertical Interval Line 15 of the Sync Signal contains a Time Tag reference for cameras to encode on their video signals.

DMC 254 Date: Apr 2014 Page: 1 Split Screen Processor Test Signals The test signals provided by the SCU include Society of Motion Picture and Television Engineers (SMPTE) color bars, a cross hatched convergence pattern test signal, a combination test and a composite test signal. This test signal is also selectable via commands received from the 1553B bus.

DMC 254 Date: Apr 2014 Page: 1 State No Test Sig EnabledEnabledEnabledDisabledDisabledDisabled Generator Spit Screen EnabledDisabledDisabledEnabledDisabledDisabled Processing Time Base DisabledEnabledDisabledDisabledEnabledDisabled Correction Power Status TIMPROM OnOnOnOnOnOn Board SSP/TBC OnOnOffOnOnOff Board Sig. Gen OnOnOnOffOffOff VFOTs SCU Normal Operation States & Board Level Power Status

DMC 254 Date: Apr 2014 Page: 1 Review Quiz In order to downlink VTR dumps, the video may require by the SCU. The Split Screen Processor and TBC can be utilized on which SCU? Can the SSP and TBC be utilized simultaneously on the same SCU?

DMC 254 Date: Apr 2014 Page: 1 Summary SCUs Two SCUs on-board SCUs provide –Split screen generation –Time base correction –Test signal generation –Synchronization of Core systems external cameras

DMC 254 Date: Apr 2014 Page: 1 Summary SCUs Split Screen Processor (SSP) and TBC can be utilized on either SCU –SSP & TBC can not be utilized simultaneously on an individual SCU –Mission/Data Planners must take into account SSP/TBC constraints when scheduling –Fixed input & output via VSUs –Split screen consists of middle 50% of each video signal processed –TBC maybe required to “stabilize” video tape source for Ku Comm Unit processing in order to downlink

DMC 254 Date: Apr 2014 Page: 1 ADACA channel Digital to Analog Conversion AIUAudio Interface Unit BADCB channel Analog to Digital Conversion BBS Master Black Burst Sync BITBuilt In Test BITE Built In Test Equipment CCCamcorder C & CCommand & Control CVIUCommon Video Interface Unit DSPDigital Signal Processor EST External Self Test EVSWExternal Video Switches FFTSFull Field Test Signal LOSLoss of Signal MCC-HMission Control Center - Houston MDMMultiplexer/DeMultiplexer MODMission Operations Directorate Acronyms

DMC 254 Date: Apr 2014 Page: 1 Acronyms Continued OBTOn-line Background built in Test POST Power On Self Test SCUSynchronization & Control Unit SSPSplit Screen Processor SWEPSwitch Enable Pulse TBCTime Base Corrector TIMPROMTime/Programmable Read Only Memory TICTelevision Camera VBITVideo Built In Test VDSVideo Distribution System VFORVideo Fiber Optic Receiver VFOTVideo Fiber Optic Transmitter VITSVertical Interval Test Signals VSUVideo Switching Unit

DMC 254 Date: Apr 2014 Page: 1 Reference Information

DMC 254 Date: Apr 2014 Page: 1 SCU Overview As stated previously, the SCU configured to provide the BBS signal will be commanded to generate Switch Enable Pulse (SWEP) commands when VSU switch configurations are modified. The purpose of the command is to execute VSU switch configurations simultaneously by sending a pulse over the BBS signal (to all of the VSUs). The SCU receives the command and generates the pulse on horizontal scan line 10 of the vertical synchronizing interval. When the VSU is configured to switch on External Sync, it will implement the previously downloaded crosspoint switch configuration after receiving the SWEP over the BBS signal.

DMC 254 Date: Apr 2014 Page: 1 Hardware Overview Interfaces SCU-1 BBS interfaces are connected to the “A” inputs on each of the VSUs. Likewise, SCU-2 BBS interfaces are connected to all of the “B” inputs on each of the VSUs. Connecting the SCUs to the VSUs in this manner makes it consistent from an operator control perspective. Each of the VSUs internal equipment configurations must be established before the VSUs are ready for routing video. Selecting the source of the BBS signal is one of those configuration commands. If SCU-1 is designated the BBS signal source, the operator configures each of the VSUs to receive sync on their “A” sync interface. This will be covered in more detail in the Video Switching Unit Course.

DMC 254 Date: Apr 2014 Page: 1 SCU Modes of Operation The five operational modes of the SCU are Power On Self Test (POST),External Self Test (EST), Built In Test Equipment (BITE), Normal Operation and Power Down/Standby. Upon power-up, the SCU immediately performs a Power On Self Test (POST) before automatically switching to the standby equipment control state. The standby state has OBT, SSP/TBC, Signal Generation functions, and all VFOTs and VFORs deactivated. Upon the receipt of a command to activate one of the SCU functions, the SCU immediately switches out of standby state, powers up the Signal Generator and enables SCU OBT. Then, it responds to the command. This is known as normal operation mode. Normal Operation can be represented by the states in Table 2.

DMC 254 Date: Apr 2014 Page: 1 SCU Modes of Operation The SSP/TBC Boards include the DSP Board, ADAC Board, BADC Board, the VFOR Boards, and the Video Output Board. The Signal Generator VFOTs represent the FFTS VFOT and the 5 VFOTs providing the BBS outputs. Whenever a command to transition to the EST or BITE Mode is received, the SCU will perform the required tests, update its BIT status data words and transition to the power standby state upon completion of the self tests.

DMC 254 Date: Apr 2014 Page: 1 Method of Control and Monitoring Similar to other video hardware items, background status monitoring of critical functions is referred to as On-line Background built in Test (OBT) which does not interfere with normal operation. The External Self Test (EST) Built in Test (BIT) testing is implemented upon command from the operator and thoroughly tests all components in the SCU. EST results in overriding all SCU functions and upon completion, leaves the SCU in the Standby Power state. The Built In Test Equipment (BITE) self test performs tests on the BITE and also overrides normal operation. The test also leaves the SCU in the Standby Power state.

DMC 254 Date: Apr 2014 Page: 1 Method of Control and Monitoring Continued During Power on Self Test (POST) and EST, VBIT performs a video quality test of the Black Burst Sync Signal, all four Test Signals, and the SSP and TBC outputs. It can also be enabled or disabled by the operator as part of the OBT. It will test those SCU video functions which are enabled. For example if the TBC is the only function active, the VBIT will test the TBC video output quality. Video BIT (VBIT) is performed during POST, and EST self tests. VBIT reports three levels of degraded video signal quality: “Off Nominal”, “Video Quality Failure” and “Video Functional Failure”.

DMC 254 Date: Apr 2014 Page: 1 SCU Hardware Details Mother Boards The SCU consists of two mother boards. One mother board is dedicated to the Fiber Optic Transmitter and Receiver functions of the SCU. The second mother board houses the Digital to Analog and Analog to Digital Conversion Boards, Analog Board, Microcontroller Board, Digital Signal Processor Board and Timing/Memory Board. The SCU also contains a Power Supply and Oscillator. Figure 3 is a functional block diagram of the SCU.

DMC 254 Date: Apr 2014 Page: 1 SCU Hardware Details Microcontroller Board The Microcontroller Board provides configuration control of the SCUs internal processes. It also provides an interface to the C&C MDM’s MIL-STD-1553B Control Bus for reception of commands and distribution of SCU status. The Microcontroller also controls power distribution to the SCU’s Boards.

DMC 254 Date: Apr 2014 Page: 1 SCU Hardware Details Video Sources The two video sources are received by two Video Fiber Optic Receiver (VFOR) Boards. These boards convert the PFM video back to an electrical baseband NTSC format. The video signal coming into Video A is transferred to the A channel Digital to Analog Conversion (ADAC) Board. This video input is used only for SSP. The B Video input is transferred to the B channel Analog to Digital Conversion (BADC) board. The B video signal can be used for TBC or SSP depending on the SCU’s configuration.

DMC 254 Date: Apr 2014 Page: 1 SCU Functional Block Diagram Figure 3

DMC 254 Date: Apr 2014 Page: 1 TBC For TBC Mode, the Digital Signal Processor (DSP) Board receives the Digitized composite video signal from the BADC Board, separates this signal into Chrominance and Luminance signals, corrects relative phasing between these signals and recombines them, then uses a frame synchronizer to TBC the video signal before transferring the signal to the ADAC Board for conversion back to the NTSC analog format. The DSP Board uses the Time/Programmable Read Only Memory (TIMPROM) Board’s synchronization signal as part of the frame synchronizing process.

DMC 254 Date: Apr 2014 Page: 1 TBC ADAC The ADAC board converts the digital signal back to Baseband analog video. The ADAC Board transfers the output to the Video Fiber Optic Transmitter (VFOT) Board which provides the SCU’s video output. For this mode, the Microcontroller does not power up the VFOR for Input Channel A.

DMC 254 Date: Apr 2014 Page: 1 Split Screen Processor For SSP Mode, both the A and B SCU video inputs are utilized. The DSP Board receives the digitized composite video signal from the BDAC Board, stores the B channel video in memory and transfers the B channel video to the ADAC Board based on timing information from the ADAC Board. The ADAC Board receives the A channel video and transfers the video to the ADAC Video Output Switch. At the midpoint of the A video horizontal scan line, the ADAC Video Output Switch selects the B Video signal from its internal memory for output.

DMC 254 Date: Apr 2014 Page: 1 Split Screen Processor ADAC/TIMPROM The ADAC Board transfers the output to the VFOT Board which provides the SCU’s Video Output. This same sequence is repeated for every line of each video field. The TIMPROM Board in conjunction with the Analog Board provides the Signal Generation function for the SCU. In addition to generating the Sync Signal, it is also capable of generating any one of four standard Video Interval Test Signals (VITS) via the Analog Board for testing the Video System. The Test Signals are provided to the SCU’s Full Field Test Signal (FFTS) Output.

DMC 254 Date: Apr 2014 Page: 1 Split Screen Processor Analog Board The Analog Board provides the BBS signal (received from the TIMPROM Board) to the VFOT BBS outputs. It can also provide VITS on the Test Signal output if configured to do so. Additionally, the Analog Board provides BIT parameter status to the TIMPROM board for relay to the Microcontroller Board.