From Practice exams Flashcards
What’s the aspect ratio of HDTV?
1.78:1
What’s the resolution of SXGA?
1280 x 1024
What two resolutions count as HDTV?
1920 x 1080(p or i), 1280 x 720p
Is HDTV transmitted analog or digitally?
Analog. Uses compression.
What is SXGA?
Super Extended Graphics Array. Standard monitor resolution, next step above XGA. 1280 x 1024 (1.25:1)
What’s the most common resolution of 17” and 19” LCD monitors?
SXGA. 1280 x 1024
Brightness control adjusts what level?
Black level.
What is Chroma?
The perceived strength of a surface color - it’s difference from grey.
Vectorscopes show…
chroma saturation (color intensity).
What is V-Sync?
For computer monitors. Makes the computer wait until the monitor has finished drawing an image before moving on to the next.
Frames per second can’t be larger than what to avoid sync issues?
Frames per second can’t be larger than your monitor refresh rate (usually between 60 and 90).
What is composite video?
Analog video transmission. Over ONE channel. No audio. Video is SD Usually on RCA jacks. Can be BNC or coax
What are the different ways sync can be sent in component video?
Separate (Red, Green, Blue, Horz Sync, Vert Sync). Composite Sync (Red, Green, Blue, Sync).
Sync-on-Green (Red, Green + Sync, Blue)
Sync-on-luminance (for YPbPr it would be on Y) (home theatre mostly)
What is chrominance?
A combination of hue and saturation.
What is S-video?
Analog video transmission
Standard Def
2 channels: Y (luma (which is luminance and synce)) and C (Chroma)
Doesn’t carry audio
Differences between Composite, S-Video, Component?
Composite: 1 channel (Fine. Low pass filter on luminance)
S-Video: 2 channels (Better)
Component: 3-5 channels (Best)
What connector is used for S-Video
4-pin. 2 signal pins and 2 grounds.
What are examples of composite video?
NTSC (Americas), PAL (Europe), SECAM (Africa, Russia)
What is component video?
Analog video transmission
Doesn’t carry audio
What is YP(B)P(R)?
A way of doing component video. Y=luma & sync, P(B) = difference between Blue and Luma, P(R) = Difference between red and luma.
What is gain in video?
On a CCD camera it’s how many electrons get converted into digital. Maximises dynamic range from each sensor.
What is a watt?
Measure of power - rate that energy is consumed or produces. 1 watt = 1 joule / second
What is an amp?
A unit for electric current. The amount of electrons passing point in a given time. 1 amp = a coulomb / second
What is a volt?
A unit for elctromotive force. The inclination of a system to allow electric current to flow.
What’s standard home voltage in the US?
120V
What’s standard home voltage in Europe/Asia?
230V
As you double distance how does it effect sound and brightness?
Sound will be 6dB less
Brightness will be 75% less
Sound levels should be how much above ambient room noise in a sound system?
25 dB
What’s an advantage of a horn loudspeaker over cone?
More efficient: 10 times (10 dB) more sound than a cone speaker.
What’s a disadvantage for a horn loudspeaker?
Frequency response is uneven. Bad bass response.
What’s the difference between RS-232 and RS-422 serial connections?
- RS-232 only allows for one transmitter and one receiver on each line. Full duplex. Ships standard on most Windows desktops.
- RS422 Faster (up to 10 Mbits/s. One transmitter can connect to a bus of up to 10 receivers. Can transmit further. Standard on Apple computers.
What’s the minimum number of wires needed to connect bidirectional RS-232?
3
Name three two cooling methods.
- Passive: air drawn in through the front. Hot air will rise and go out the top and rear of the rack. Vented shelves and panels at the back will help create that airflow.
- Forced. Fans on top. Fan top and bottom doesn’t help; more fans on top do.
First steps of designing a AV system?
- Site survey. Gather numbers, see what’s there. Count celing tiles to guess room size (usually 2x4). See if you can get construction drawings. Start with reflected ceiling plan.
- Get feedback from customer. How do they want to use the space.
- Design phase.
What is screen gain?
Is the ability of a screen to redirect projected light to the audience to make it appear brighter.
What are standard measurements for light?
Candela, Lux, Nits
What is a CCD in a video camera?
A light sensitive electronic chip called a charge coupled device
Composite video is made by…
combining the luminance and chroma information onto one cable
What are the four teams that comprise the overall Project Team?
Owner, Design, Installation, and Management
What team would the lighting consultant belong on?
Design
What groups would make up the Management team?
Developer, Construction Manager, and Building Management Agency
Who’s on the owner team?
End-User, Facility Manager, and Building Committee
What are three roles important to the Project process?
Project Mangers, Designers, and Installers
What project characteristics need to be considered in order to determine which method is best suited for a particular project?
Schedule, Size, Type, Complexity, and Procurement Requirements
Which of these would have a direct impact on the project process and design/installation: Overhead funding, Technical Support Funding, Staffing Funding, Training funding
Technical Support Funding
What are 4 milestones that must be achieved in a typical project schedule?
Programming, Building Design, AV Bid, and Move-in
Dielectric constant
relative permittivity - how well something insulates. Used in describing cable insulation.
Common cable insulators?
PVC or Teflon
What is DB9A?
A type of connector used for control and video signal transport.
How many conductors in a RJ-45?
8 pin, 8 conductor (8P8C)
What’s the difference between DVI-D and DVI-I?
DVI-D has 24 pins and carries only digital signal. DVI-I (is is for interlaced) has 29 pins and allows analog and digital to be transmitted. Neither carries audio.
How many pins in VGA?
15
Do DisplayPort and HDMI carry audio?
Yes.
What does HDMI stand for?
High-Definition Multimedia Interface
What are SDI and HD-SDI?
Used for high quality digital video. Production and videoconferencing systems. Uses coax cable and BNC connectors.
Inductance?
The property of a circuit that opposes any change in current.
Capacitance?
The property of a circuit that opposes any change in voltage.
Two types of switches?
Mechanical and smooth (used for presentation. Monitors sync and synchronizes the transition to when it’s in vertical retrace).
How wide is the inside of a standard AV rack?
19 inches; 482.6 mm
How big is one rack unit?
1.75 in; 44 mm
What’s a signal seperation diagram?
shows the back of a rack and the cables that connect each piece of equipment.
What’s a “button by button” document?
narrates what happens when someone presses a button on a control system interface.
What’s the difference between a function and a macro?
Function is an individual action. Macro are several functions initiated by pressing just one button.
What are distributed intelligence, distributed processing, or edge appliances?
Advanced configurations that let a control system control stuff in multiple rooms or another part of the world.
What’s a contact-closure control system?
A switch. Basic protocol language (on or off) and works by opening or closing an electrical current or voltage loop. Ex. projection screens, drapes. Use a low-voltage interface.
Which control system uses a low-voltage interfaces?
Contact-closure.
What’s variable-voltage control or voltage ramp generator?
Ex. light dimming, camera’s pan/tilt head. As voltage changes at the control point the device adjusts it’s level by a specific ratio.
How does optical IR control work?
A LED emits a pattern of light pulses in IR range. The control point on device recognizes those patterns and then does stuff.
Range of IR?
30-40 feet.
Range of RF control?
about 100 ft
What are RS-232, RS-422, and RS-485?
Types of control system cabling
RS-232?
Unbalanced, common, shorter cable runs. Uses DB9 or DB25 connectors. Point to point.
RS-422?
Longer cable runs, balanced, multidrop but one transmitter.
RS-485?
Supports 32 transmitting and receiving devices or way more. Balanced.
Impedance is in AC or DC?
AC!!!! Includes resistance AND reactance
What’s the range of RF in the electromagnetic spectrum?
3kHz to 300 GHz
What’s the programming phase?
Needs analysis. The term architects use for the beginning of a project when you’d be doing a needs analysis.
What to look at for a needs analysis?
- Specific activities end users will do.
- Required AV presentation applications
- Fasts and functions that support the applications.
What’s the detailed report built out of a needs analysis?
Program Report, or Brief.
Is budget included in a program report?
Yep. It’s one of the overall functional needs of the AV system based on tasks the owner requires for operation.
What would be some parameters of the AV task “interconnection of spaces”?
Identification of source spaces & destination spaces, Number type resolution and format of audio and video signals to be connected, one way or two way, etc
In a needs analysis functions, equipment, task, and applications go in what order of importance?
End user needs (big picture: reduce travel time), applications( videoconferencing) tasks (audio and visual presentations), Functions (sight lines, AV systems, seating layout)
