CTS-I – Certified AV Installation Specialist Test
how many times a digital sample is taken of the analog sample, per second
Ex. CD Sampling rate = 44.1kHz
Called Pulse Code Modulation (PCM)
Determines digital signal's accuracy - answers✔✔• Analog to Digital Conversion: Sampling Rate
• Analog sig must be encoded at rate 2X or more than highest freq. of sample
• Human hearing is up to 20kHz -> digital audio should be at least 40 kHz - answers✔✔Nyquist-
Shannon Sampling Thm
Number of bits used to describe a sampled voltage level -> "quantization"
Assigns quantity to the signal being measured
Greater bit depth = more accurate rep of signal
• i.e. if sig has on bit -> 0 or 1-> describes only two states, on or off
• 2 bits= 4 states
• CD has 16 bits -> 216
In video, bit depth is how many shades can be described - answers✔✔o Bit depth
Measures quantity of info over time in a dig. Signal stream
Bits per second bps
Higher bps = higher quality - answers✔✔o Bit Rate
,Reducing file size to smaller, more manageable
Remove unnecessary info
In text files, spaces compressed without affecting words
In videos, use codec for transfer
• Usually 5:1 compression - answers✔✔o Compression
Converts analog to dig for both audio and video
Conserves bandwidth - answers✔✔o Codec
Container - structure of file where data is stored
• Defines how data is arranged to inc. performance when codecs used
• i.e. WMV
Codec - answers✔✔o 2 elements of digital file:
never loses quality
Larger file sizes
i.e. winzip - answers✔✔o Lossless compression
approx. of original data, eliminates unnecessary or redundant info
Multiple reopening with degrade file - answers✔✔o Lossy compression
Analog
• Need amplifiers for analog signals cause losses
• Amplifiers make noise worse
• Degradation
Digital
,• Not affected
• Discerning circuitry helps rebuild - answers✔✔o Noise
devices sharing the data, sends or receives - answers✔✔o Nodes
- physical means by which data travels between nodes - answers✔✔o Connections
any device that connects to network must have one
Interface that allows you to connect to network
Has own MAC - answers✔✔o NIC
hardware address
ID for the network
48 bit number, 6 groups of 2 hexidecimal numbers
• First part manufacturer, second is serial # - answers✔✔o MAC
provides phys connection btwn multiple devices
Stores each MAC address
Communication w/ parts via Ethernet
Either managed or unmanaged
Managed is configurable -> VLANs, monitor traffic, etc. - answers✔✔o Switch
forwards data between devices not directly connected
Border between Lan and Wan
Uses IP address - answers✔✔o Router
, router that connects private to public IPs
Translates between protocols
• Private uses baseband, public uses broadband - answers✔✔o Gateway
provides a service to dependent nodes
can be a program, computer hardware
often hosted on several computers
thin server - provides one service - answers✔✔o Server
Copper - uses Voltage
Optical Fiber
Wifi - answers✔✔• Network Connections
o 3 Most common
• Twisted pair
o "cats"
o Under Ethernet standards - answers✔✔Copper - uses Voltage
designation for 100 Ohm unshielded twisted pair cables
100 MHz - 100 Mbps and 1Gbps
Adds specs for far end crosstalk - answers✔✔o Cat 5e
more twists per inch
250 MHz - 100 Mbps and 1Gbps
Higher speeds -> higher freq. with tiny wavelengths
Susceptible to noise
how many times a digital sample is taken of the analog sample, per second
Ex. CD Sampling rate = 44.1kHz
Called Pulse Code Modulation (PCM)
Determines digital signal's accuracy - answers✔✔• Analog to Digital Conversion: Sampling Rate
• Analog sig must be encoded at rate 2X or more than highest freq. of sample
• Human hearing is up to 20kHz -> digital audio should be at least 40 kHz - answers✔✔Nyquist-
Shannon Sampling Thm
Number of bits used to describe a sampled voltage level -> "quantization"
Assigns quantity to the signal being measured
Greater bit depth = more accurate rep of signal
• i.e. if sig has on bit -> 0 or 1-> describes only two states, on or off
• 2 bits= 4 states
• CD has 16 bits -> 216
In video, bit depth is how many shades can be described - answers✔✔o Bit depth
Measures quantity of info over time in a dig. Signal stream
Bits per second bps
Higher bps = higher quality - answers✔✔o Bit Rate
,Reducing file size to smaller, more manageable
Remove unnecessary info
In text files, spaces compressed without affecting words
In videos, use codec for transfer
• Usually 5:1 compression - answers✔✔o Compression
Converts analog to dig for both audio and video
Conserves bandwidth - answers✔✔o Codec
Container - structure of file where data is stored
• Defines how data is arranged to inc. performance when codecs used
• i.e. WMV
Codec - answers✔✔o 2 elements of digital file:
never loses quality
Larger file sizes
i.e. winzip - answers✔✔o Lossless compression
approx. of original data, eliminates unnecessary or redundant info
Multiple reopening with degrade file - answers✔✔o Lossy compression
Analog
• Need amplifiers for analog signals cause losses
• Amplifiers make noise worse
• Degradation
Digital
,• Not affected
• Discerning circuitry helps rebuild - answers✔✔o Noise
devices sharing the data, sends or receives - answers✔✔o Nodes
- physical means by which data travels between nodes - answers✔✔o Connections
any device that connects to network must have one
Interface that allows you to connect to network
Has own MAC - answers✔✔o NIC
hardware address
ID for the network
48 bit number, 6 groups of 2 hexidecimal numbers
• First part manufacturer, second is serial # - answers✔✔o MAC
provides phys connection btwn multiple devices
Stores each MAC address
Communication w/ parts via Ethernet
Either managed or unmanaged
Managed is configurable -> VLANs, monitor traffic, etc. - answers✔✔o Switch
forwards data between devices not directly connected
Border between Lan and Wan
Uses IP address - answers✔✔o Router
, router that connects private to public IPs
Translates between protocols
• Private uses baseband, public uses broadband - answers✔✔o Gateway
provides a service to dependent nodes
can be a program, computer hardware
often hosted on several computers
thin server - provides one service - answers✔✔o Server
Copper - uses Voltage
Optical Fiber
Wifi - answers✔✔• Network Connections
o 3 Most common
• Twisted pair
o "cats"
o Under Ethernet standards - answers✔✔Copper - uses Voltage
designation for 100 Ohm unshielded twisted pair cables
100 MHz - 100 Mbps and 1Gbps
Adds specs for far end crosstalk - answers✔✔o Cat 5e
more twists per inch
250 MHz - 100 Mbps and 1Gbps
Higher speeds -> higher freq. with tiny wavelengths
Susceptible to noise
