64 QAM Flashcards
Forms the foundation for current high-speed data transfer via the cable system
Docsis
First Docsis release date
March 1997
Docsis 2 release date
January 2002
the basic transmission standard and created the ability for the Cable Modem Termination System (CMTS) to talk to the cable modem in the customer’s house
DOCSIS 1.0
Provided the control and enhanced security lacking in DOCSIS 1.0
DOCSIS 1.1
supports higher upstream speed by allowing for additional profiles, triples the maximum upstream capacity, enable transmission across 6.4 MHz channel and increase upstream throughput to 30.72 Mbps by using 64 or 128 QAM
DOCSIS 2.0
provides improved CMTS upstream reception, better FEC, ingress cancellation and provides increased upstream spectrum availability
DOCSIS 2.0
features channel bonding, which enables multiple downstream and upstream channels to be used together at the same time by a single subscriber
DOCSIS 3.0
channel bonding supports IPv6 standards and expands the number of available IP addresses from existing 8 to 16-bit strings to as much as 32- and 128-bit strings
DOCSIS 3.0
are transmitted at a fixed frequency and are comprised of a string of on and off states usually referred to as one’s and zero’s
Digital Communications
Non-Linear distortions occur during modulation (caused by electronics and equipment), Noise accumulates as the signal propagates, and received signal has been degraded by both noise and distortion
Analog Transmission System
Digitizing errors occurs during analog to digital conversion,
noise accumulates as the signal propagates, receiver can accurately distinguish between one and zero state
Digital Transmission System
the process of recording each sample as a number corresponding to the amplitude of the signal at that time
Quantizing
the process of measuring an analog signal at specific intervals so that a digitized signal can created to represent the original analog waveform
Sampling
principle that engineers follow in the digitization of analog signals
Nyquist Theorem
