The favoured carrier modulation scheme for downstream traffic is Quadrature Amplitude Modulation or QAM. 2.2. Internet traffic between cable modem and modem termination systems. Smart modems typically require more bandwidth than transparent modems, and typically achieve higher data rates. A more efficient modulation scheme, OFDMA, is expected to play a bigger role as cable operators start to embark on upgrades that dedicate more spectrum to the upstream. ... on the other hand, the modulation scheme can use phase shifts of 45, 135, 225, or 315 degrees, each modulated carrier pulse transmits 2 bits of information. Cable Modem Terminal Server c. Cable Modem Terminal System b. Except for a few analog cellphone models, you cannot plug your cellphone into your laptop’s land-based modem even if the cable fits. The order of the QAM modulation has to be set at the transmitter, because the transmission is only one way, and in addition to this, there are thousands of receivers, making it impossible to have a dynamically adaptive form of modulation. A "splitter" at the subscriber end is not required for: a. Cable modems must be DOCSIS-compliant. Some ADSL modems use coded orthogonal frequency division modulation. They sense the channel conditions and adapt the modulation scheme to obtain the highest data rate for the given conditions. The input signal . The modulation scheme selected for the downstream is one of a number of modulation schemes available on the downstream communication channel selected. If you are looking for a reviewer in Communications Engineering this will definitely help. Modulation is a process through which audio, video, image or text information is added to an electrical or optical carrier signal to be transmitted over a telecommunication or electronic medium. The IEEE 802.11 standard defines a short range modulation scheme that is used on a large scale … The proposed modem is implemented in Altera EP3C16E144C8 device, together with an 8-bit ADC and a BPF. The modulation process places (analog or digital) signalinformation onto sinewave carriers while demodulation reverses theprocess at the receiving end. Coded Modulation: TCM, TTCM, BICM, BICM-ID Studies Trellis Coded Modulation (TCM), Turbo Trellis Coded Modulation (TTCM), Bit-Interleaved Coded Modulation (BICM), Iterative BICM (BICM-ID) and compares them under various … For domestic broadcast applications for example, 64 QAM and 256 QAM are often used in digital cable television and cable modem applications. The changes in the carrier signal are chosen from a finite number of M alternative symbols (the modulation … A cable modem termination system, comprising: a transmitter for sending chunks of data to one or more cable modems on a downstream channel; and signaling circuitry configured to insert a wake up message into the chunks of data on the downstream channel for causing a device to exit a low power mode, where the signaling … Shortened Codewords in DOCSIS 3.1 Cable Modem System Joon … The QAM modulation is typically used in CATV system for cable modem transmission. There are wireless modems for laptops, handhelds and cellphones. Quadrature Amplitude Modulation, or QAM, is an everyday modulation scheme used in today’s telecommunications world. This tends to be a rather noisy part of the electromagnetic spectrum. Therefore it is important that the usage of this resource is minimized by carefully designing the digital modems. Cable Modem Transmission System d. Cable Modem Transmission Server ANS: A 35. fc. On most cable systems, upstream communication takes place in the frequency range between 5 and 40 MHz. In many radio communications and data delivery applications. Digital modulation methods can be considered as digital-to-analog conversion and the corresponding demodulation or detection as analog-to-digital conversion. 1 Cable Modem 通訊網路簡介與實驗 Presenter: Shi Yen Huang Introduction zSpectrum allocation – Upstream : 5 – 42 MHz – Downstream : 54 – 750 MHz z54 - 550MHz for Analog TV program signal. The carrier frequency of the OOK modulated signals is 2.176 MHz. Today’s DOCSIS modems rely on a reservation scheme where the modems request a time to transmit and the CMTS grants time slots based on availability. Quadrature Phase Shift Keying (QPSK) Another extension of PSK is the digital modulation technique which is a higher order of PSK that uses a four level phase state to transmit 2bits/symbol simultaneously, by selecting one of the four possible equally spaced carrier phase shift of 0, π/2, π and 3π/2, where each value … Audio Frequency Shift Keying (AFSK): Is a special FSK modulation scheme using two tones, 2200 and 1200Hz, to modulate a ... cable modem QPSK, DQPSK Satellite, CDMA, NADC ... telemetry pilots for monitoring broadband video systems 16 QAM Digital microwave radio, modem, DVB -C, DVB -T 32 QAM Terrestrial microwave 64 QAM DVB -C, modem … Much of the work on modulation techniques currently benefiting the cable modem industry stems from interest in digital video and from technology developed for telephony. ... including in cellular and cable modem applications . Multiple cable modems attached to a single cable can use the same frequency band, using a low-level media access protocol to allow them to work … DSL, or Digital Subscriber Line, is a modulation scheme that uses an existing 2-wire copper telephone line to provide high speed internet without holding up the phone line.. At 30 Mbps, cable speeds … If cable modems go offline, or appear to be online but do not pass traffic when in the mixed TDMA/A-TDMA mode, upgrade the modem software to a … z550 - 750 MHz for data traffic or digital TV program signal zModulation Scheme – Upstream : QPSK or 16 QAM, Bit Rate 0.32 … … 11/18/14 12 The cable physical plant must be capable of supporting the higher-bandwidth DOCSIS 2.0 A-TDMA modulation profiles. Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. Provide cable modem users with data privacy across the cable network; The modem is fully compliant with the 3GPP and … Any DSL scheme c. ADSL Lite b. ADSL d. none of the above m (t Frequency Modulation. I can assure you that this will be a great help in reviewing the book in preparation … The paper proposes an e cient scheme for combining asynchronous and synchronous tra c on the 5 Because of the relatively noisy nature of the upstream channel, cable modems must be capable of transmitting only QPSK and 16-QAM. 16. Digital modulation methods. The method of claim 14, wherein the selected modulation scheme is QAM-64. Cable-modem (CM) technology is being developed to provide high-speed multimedia services to the subscribers’ homes over the existing hybrid- ber-coax (HFC) infrastructure of cable TV networks. In digital modulation, an analog carrier signal is modulated by a discrete signal. is the process of encoding source data onto a carrier signal with frequency . For domestic broadcast applications for example, 64 and 256 QAM are often used in digital cable television and cable modem applications. Cable modem. While most of us don’t see it, this modulation technique is used in DSL, Cable Modem, wireless, HDTV, fiber-optic communications and more. The IEEE 802.14 Cable Modem standard is still being defined, while a plethora of vendors is contending for the existing customer base with a range of generally similar but essentially proprietary and mutually incompatible … SP-CMC1-102-980317 (Mar. It conveys two analog message signals, or two digital bit streams, by changing (modulating) the amplitudes of two carrier waves, using the amplitude-shift keying (ASK) digital modulation … CONCLUSION QAM is an important modulation scheme because of its widespread adoption in current technologies. This technique is called Quadrature Phase Shift Keying (QPSK) ! Modulation enables the transfer of information on an electrical signal to a receiving device that demodulates the … Introduction. ADSL (asymmetric digital ... it is often possible to get better performance or make other parts of the system simpler by using radio frequencies and modulation techniques through a cable. Different modulation schemes based on cable modem performance Level of Modulation is based on MER at the CPE. A method of synchronizing the local clock in a cable modem (CM) to a remote clock at a cable modem termination system (CMTS), ... wherein the predetermined interval is based on the symbol rate of the selected modulation scheme. Abstract—A new type of power line carrier communication (PLC) technique is developed to reduce cable requirements for robotic and vehicular systems. This is the Multiple Choice Questions in Chapter 12: Digital Modulation and Modems from the book Electronic Communication Systems by Roy Blake. The IEEE 802.11 standard defines a short range modulation scheme that is used on a large scale throughout the … Cable modems are assigned a Service ID (SID) that is mapped to class of service (CoS) or quality of service (QoS) parameters. Router# show running-config | in service flow cable service flow priority Router# show cable modem 100.1.2.110 verbose MAC Address : 0025.2e2d.74f8 IP Address : 100.1.2.110 IPv6 Address : 2001:420:3800:909:7964:98F3:7760:ED2 Dual IP : Y Prim Sid : 1 Host Interface : … 11, Bluetooth, CDPD, DataTAC, Mobitex and Ricochet. a. It operates at variable data rates of 9.6, 38.4, and 115.2 kbps based on the OOK modulation scheme. The cable companiesare offering broadband services with cable modems. In either case,modulations are one of the fundamental technologies. Wireless modems support several technologies, including 802. 15. The project file The project file “QAM – Transmitter and Receiver.osd” has an QAM transmitter and receiver (Figure 1) using a 64 QAM transmission (6 bits per symbol). Amplitude modulation is used in computer modems, VHF aircraft radio, and in portable two-way radio. Cable modems use a range of frequencies originally intended to carry RF television channels. All modulation techniques involve operation on one or more of the three fundamental frequency domain parameters: amplitude, frequency, and phase. Modulation. The downstream channel will occupy the 6 MHz bandwidth of a television channel, allowing the provider to slot cable modem channels into unused television slots in his cable bandwidth. Cable Internet is a broadband Internet connection designed to run through your TV's local cable by connecting it to a modem. While MPEG-2 is becoming the digital video standard for the broadcast industry, digital modulation techniques allow vendors to squeeze 6 or more digital … In this type of modulation, the frequency of the carrier signal varies in accordance with the message signal, and other parameters like amplitude and phase remain constant. QAM is also used in Bluetooth. Data-Over-Cable Service Interface Specifications, Cable Modem to Customer Premise Equipment Interface Specification. Portrays Redundant Residue Number System (RRNS) based codes and their turbo decoding. Quadrature Modulation Schemes!! The US cable modem industry is at this time in a similar position to the networking industry in the mid eighties. 3. Moreover, this scheme can be implemented in LabVIEW with the use of the NI Modulation … Television channels the corresponding demodulation or detection as analog-to-digital conversion is the Multiple Choice Questions in Chapter 12: modulation! 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