Today is a last day for blog SCCT 1023. Tomorrow is already October, I have feel that my sem 3 is become end. Yesterday my course mate tell me our add drop week is held on next week. Alamak, I not yet arrange my time table but ‘m sure that I will minor tourism. Haiz…our group presentation held on this coming Sunday, also the intercultural. Miss Noorazura also reminds us regarding the blog check list and evaluation form of our group members. And our 2nd quiz is coming soon…
Thanks for Miss Noorazura because teaching us all about technology communication, I want would like apologize if I have make any mistaken.
2009年10月4日星期日
18th lecture: 27/9/09
Today is my 1st class after Holiday Raya. But then I didn’t attend class for today because I need attend activity ‘ Exhibition Mooncake Festival Charity 2009’ at foyer library. Because I’m Treasure 2 for this activity.
17th lecture: 13/9/09
Today is a last lecture for SCCT 1023 because Miss Noorazura cancelled already the Wednesday class. Today also must submit our 2nd individual assignment. Haiz…. Why we have a lot of assignment want to do. I have feel stress because I scare I can’t handle it. By the way, I finished it also and submit it on today.
RCA connector
An RCA connector, sometimes called cinch plug or lotus plug, is a type of electrical connector that is commonly used in the audio/video market. The name "RCA" derives from the Radio Corporation of America, which introduced the design by the early 1940s to allow mono phonograph players to be connected to amplifiers.
For many other applications it began to replace the older jack plugs used in the audio world when component high fidelity started becoming popular in the 1950s.
The corresponding plug is called an RCA plug or phono plug, for "phonograph". The name "phono plug" is often confused with a "phone plug" which refers to a jack plug or TRS connector.
In the most normal usage, cables have a standard plug on each end, consisting of a central male connector, surrounded by a ring. The ring is often segmented for flexibility. Devices mount the jack, consisting of a central hole with a ring of metal around it. The ring is slightly smaller in diameter and longer than the ring on the plug, allowing the plug's ring to fit tightly over it. The jack has a small area between the outer and inner rings which is filled with an insulator, typically plastic (very early versions, or those made for use as RF connectors used ceramic).
As with many other connectors, the RCA has been adopted for other uses than originally intended, including as a power connector, an RF connector, and as a connector for loudspeaker cables. Its use as a connector for composite video signals is extremely common, but provides poor impedance matching. RCA connectors and cable are also commonly used to carry S/PDIF-formatted digital audio, with plugs colored orange to differentiate them from other typical connections.
Connections are made by pushing the cable's plug into the female jack on the device. The signal-carrying pin protrudes from the plug, and often comes into contact with the socket before the grounded rings meet, resulting in loud hum or buzz if the audio components are powered while making connections. Continuous noise can occur if the plug partially falls out of the jack, breaking ground connection but not the signal. Some variants of the plug, especially cheaper versions, also give very poor grip and contact between the ground sheaths due to their lack of flexibility.
They are often color-coded, yellow for composite video, red for the right channel, and white or black for the left channel of stereo audio. This trio (or pair) of jacks can be found on the back of almost all audio and video equipment. At least one set is usually found on the front panel of modern TV sets, to facilitate connection of camcorders (through 3.5mm Jack to 3 RCA, also called Mini RCA plug), digital cameras, and video gaming consoles. Although nearly all audio-visual connectors, including audio, composite and component video, and S/PDIF audio can use identical 75 Ω cables, sales of special-purpose cables for each use have proliferated. Varying cable quality means that a cheap line-level audio cable might not successfully transfer component video or digital audio signals due to impedance mismatch and poor shielding quality (causing signal-to-noise ratio to be too low). Cables should meet the S/PDIF specification as defined by the international standard IEC 60958-3 for assured performance.
The male plug has a center pin which is 3.70 mm in diameter, and is surrounded by an outer shell which is 8.25 mm in diameter
One problem with the RCA jack system is that each signal requires its own plug. Even the simple case of attaching a cassette deck may need four of them, two for stereo input, two for stereo output. In any common setup this quickly leads to a mess of cables, which is made worse if one considers more complex signals like component video (a total of three for video and two for analog audio or one for digital coaxial audio).
There have been numerous attempts to introduce combined audio/video connectors for direct signals[citation needed]but in the analog realm none of these have ever become universal, except in Europe where the SCART connector is very successful[citation needed]. For a time the 5-pin DIN connector was popular for bi-directional stereo connection between A/V equipment, but it has been entirely displaced[citation needed] on modern consumer devices. Though RF modulators inherently transmit combined A/V signals in video applications, they depend on broadcast television systems and RF connectors which are not universal worldwide; RF signals are also generally inferior to direct signals due to protocol conversion and the RF limitations of the three major analog TV systems (NTSC, PAL and SECAM).
Nearly all modern TV sets, VCRs, and DVD players sold in Europe have SCART connectors[citation needed], though sometimes supplemented by RCA and/or RF connectors and there are also SCART-RCA adapters.[1] Outside Europe, separate RCA connectors are the norm[citation needed], supplemented by RF connectors for backward compatibility and simplicity; though mini-DIN connectors are sometimes used for S-Video connections, composite video, component video, and analog audio (mono or stereo) all use RCA connectors unless RF is used. In the digital realm, however, combined A/V connectors are gaining ground; HDMI is commonly being used today, and DisplayPort is a potential competitor to HDMI.
For audio signals, an RCA connection is called unbalanced, and a true balanced connection is generally preferred in certain applications because it allows for the use of long cables while reducing susceptibility to external noise.
16th lecture: 9/9/09
Lecture today still is telecommunication, but Miss Noorazura is teaching Facsimile System and Paging System.
Facsimile System is a copy or reproduction of an old book, manuscript, map, art print or other item of historical value that is as true to the original source as possible using, normally, some form of photographic technique. It differs from other forms of reproduction by attempting to replicate the source as accurately as possible in terms of scale, color, condition, and other material qualities. For books and manuscripts, this also entails a complete copy of all pages; hence an incomplete copy is a "partial facsimile". Facsimiles are used, for example, by scholars to research a source that they do not have access to otherwise and by museums and archives for museum and media preservation. Many are sold commercially, often accompanied by a volume of commentary. They may be produced in limited editions, typically of 500–2,000 copies, and cost the equivalent of a few thousand United States dollars.
Paging System is an important part of virtual memory implementation in most contemporary general-purpose operating systems, allowing them to use disk storage for data that does not fit into physical RAM. Paging is usually implemented as architecture-specific code built into the kernel of the operating system. In computer operating systems there are various ways in which the operating system can store and retrieve data from secondary storage for use in main memory. One such memory management scheme is referred to as paging. In the paging memory-management scheme, the operating system retrieves data from secondary storage in same-size blocks called pages. The main advantage of paging is that it allows the physical address space of a process to be noncontiguous. Prior to paging, systems had to fit whole programs into storage contiguously which caused various storage and fragmentation problems.
Facsimile System is a copy or reproduction of an old book, manuscript, map, art print or other item of historical value that is as true to the original source as possible using, normally, some form of photographic technique. It differs from other forms of reproduction by attempting to replicate the source as accurately as possible in terms of scale, color, condition, and other material qualities. For books and manuscripts, this also entails a complete copy of all pages; hence an incomplete copy is a "partial facsimile". Facsimiles are used, for example, by scholars to research a source that they do not have access to otherwise and by museums and archives for museum and media preservation. Many are sold commercially, often accompanied by a volume of commentary. They may be produced in limited editions, typically of 500–2,000 copies, and cost the equivalent of a few thousand United States dollars.
Paging System is an important part of virtual memory implementation in most contemporary general-purpose operating systems, allowing them to use disk storage for data that does not fit into physical RAM. Paging is usually implemented as architecture-specific code built into the kernel of the operating system. In computer operating systems there are various ways in which the operating system can store and retrieve data from secondary storage for use in main memory. One such memory management scheme is referred to as paging. In the paging memory-management scheme, the operating system retrieves data from secondary storage in same-size blocks called pages. The main advantage of paging is that it allows the physical address space of a process to be noncontiguous. Prior to paging, systems had to fit whole programs into storage contiguously which caused various storage and fragmentation problems.
15th lecture: 6/9/09
Lecture today is talking about telecommunication. I think cell phone is 1 of the most important thing to us at now, this is because we need use cell phone to contact each other everyday. Before I come in UUM, mostly I sms with my friend. After I come in UUM and I register Digi Campus, I always talking with my friend, and the same time, I seldom sms with my friend. This is because I lazy to typing message, and directly call to my friend and talking with them.
I still remembered my 1st cell phone is Nokia 2100 when i'm form 2, after that I change to Samsung. It just included some simple function but now it's much more high technology already because it also including 3G, bluetooth, wap and so on...Now I’m using Sony Ericsson k810i.
I still remembered my 1st cell phone is Nokia 2100 when i'm form 2, after that I change to Samsung. It just included some simple function but now it's much more high technology already because it also including 3G, bluetooth, wap and so on...Now I’m using Sony Ericsson k810i.
14th lecture: 2/9/09
RazakSAT
RazakSAT is a Malaysian satellite carrying a high-resolution camera. It was launched into low Earth orbit by a Falcon 1 rocket on July 14, 2009. It was placed into an unique near-equatorial orbit that presents many imaging opportunities for the equatorial region.
RazakSAT is a Malaysian satellite carrying a high-resolution camera. It was launched into low Earth orbit by a Falcon 1 rocket on July 14, 2009. It was placed into an unique near-equatorial orbit that presents many imaging opportunities for the equatorial region.
Background
This satellite is Malaysia's second remote sensing satellite after TiungSAT-1, which was launched in September 26, 2000 on a Ukrainian Dnepr rocket from Baikonur, Kazakhstan.
Originally called MACSAT, RazakSAT's payload is mainly electro-optical, carrying a Medium-sized Aperture Camera (MAC) which is a pushbroom camera with five linear detectors (one panchromatic, four multi-spectral) weighing approximately 50 kg. The entire satellite weighs at about 180 kg.
The then-Prime Minister of Malaysia, Mahathir Mohamad renamed the satellite to RazakSAT in tribute to the second Prime Minister of Malaysia, Abdul Razak or known as the "Bapa Pembangunan Malaysia" (Father of Malaysian Development) for his contribution to Malaysia's development. This was held officially during Mahathir's working visit to Astronautic Technology (M) Sdn. Bhd. (ATSB) in 2003 at its premise in Technology Park Malaysia (TPM) in Bukit Jalil, Kuala Lumpur. It has since moved to its new premises at Hicom-Glenmarie Industrial Park, Shah Alam, Selangor. ATSB is a wholly-owned company of the Minister of Finance Inc. (MOF) and reports to the Ministry of Science, Technology and Innovation (MOSTI), Malaysia.
This satellite is Malaysia's second remote sensing satellite after TiungSAT-1, which was launched in September 26, 2000 on a Ukrainian Dnepr rocket from Baikonur, Kazakhstan.
Originally called MACSAT, RazakSAT's payload is mainly electro-optical, carrying a Medium-sized Aperture Camera (MAC) which is a pushbroom camera with five linear detectors (one panchromatic, four multi-spectral) weighing approximately 50 kg. The entire satellite weighs at about 180 kg.
The then-Prime Minister of Malaysia, Mahathir Mohamad renamed the satellite to RazakSAT in tribute to the second Prime Minister of Malaysia, Abdul Razak or known as the "Bapa Pembangunan Malaysia" (Father of Malaysian Development) for his contribution to Malaysia's development. This was held officially during Mahathir's working visit to Astronautic Technology (M) Sdn. Bhd. (ATSB) in 2003 at its premise in Technology Park Malaysia (TPM) in Bukit Jalil, Kuala Lumpur. It has since moved to its new premises at Hicom-Glenmarie Industrial Park, Shah Alam, Selangor. ATSB is a wholly-owned company of the Minister of Finance Inc. (MOF) and reports to the Ministry of Science, Technology and Innovation (MOSTI), Malaysia.
Launch
SpaceX launched RazakSAT at 03:35 UTC on July 14, 2009 using a Falcon 1 rocket. This was the fifth flight of a Falcon 1, and like the previous flights lift-off was from Omelek Island in the Kwajalein Atoll. At 05:25 UTC Elon Musk, founder and CEO of SpaceX, told a reporter the launch had been a success. "We nailed the orbit to well within target parameters...pretty much a bullseye." Musk said.
Operations
RazakSAT's mission plan will be carried out by engineers from ATSB. Control operations will be conducted through Malaysian National Space Agency 's Ground Station in Banting, Selangor and ATSB's ground station in Shah Alam, Selangor consisting of a Mission Control Station (MCS) and Image Receiving and Processing Station (IRPS). Another Malaysian ground station which would be able to receive images from the satellite is the Remote Sensing Malaysia groundstation in Temerloh, Pahang. The IRPS will receive and archive images for post processing and distribution to the users.
RazakSAT is unique as it will be the first microsatellite of its class to be placed at Near equatorial orbit (NEqO); unlike many other satellites of its kind that are placed on Sun-Synchronous Orbit (SSO). RazakSAT's orbital inclination will coincide with the latitude of its launch at Kwajalein, and that of the northernmost extent of Malaysia. Thus its launch will be nearly due east and quite efficient.
This is especially important because Malaysia is usually covered by the equatorial cloud bands. Normal sun-synchronous optical satellites, which may re-visit an area only once every 14 days, will almost never be able to see the ground during their pass. As a result, much optical imagery of Malaysia is years out of date.
RazakSat, on the other hand, will revisit some part of Malaysian territory every 90 minutes, maximising its ability to exploit gaps in the clouds, and substantially improving coverage of the country as a result.
SpaceX launched RazakSAT at 03:35 UTC on July 14, 2009 using a Falcon 1 rocket. This was the fifth flight of a Falcon 1, and like the previous flights lift-off was from Omelek Island in the Kwajalein Atoll. At 05:25 UTC Elon Musk, founder and CEO of SpaceX, told a reporter the launch had been a success. "We nailed the orbit to well within target parameters...pretty much a bullseye." Musk said.
Operations
RazakSAT's mission plan will be carried out by engineers from ATSB. Control operations will be conducted through Malaysian National Space Agency 's Ground Station in Banting, Selangor and ATSB's ground station in Shah Alam, Selangor consisting of a Mission Control Station (MCS) and Image Receiving and Processing Station (IRPS). Another Malaysian ground station which would be able to receive images from the satellite is the Remote Sensing Malaysia groundstation in Temerloh, Pahang. The IRPS will receive and archive images for post processing and distribution to the users.
RazakSAT is unique as it will be the first microsatellite of its class to be placed at Near equatorial orbit (NEqO); unlike many other satellites of its kind that are placed on Sun-Synchronous Orbit (SSO). RazakSAT's orbital inclination will coincide with the latitude of its launch at Kwajalein, and that of the northernmost extent of Malaysia. Thus its launch will be nearly due east and quite efficient.
This is especially important because Malaysia is usually covered by the equatorial cloud bands. Normal sun-synchronous optical satellites, which may re-visit an area only once every 14 days, will almost never be able to see the ground during their pass. As a result, much optical imagery of Malaysia is years out of date.
RazakSat, on the other hand, will revisit some part of Malaysian territory every 90 minutes, maximising its ability to exploit gaps in the clouds, and substantially improving coverage of the country as a result.
Satellite bus
The satellite bus used for RazakSAT was jointly developed by ATSB and Satrec Initiative, a commercial satellite manufacturer in Korea. Satrec Initiative markets the bus system as the "SI-200".
The satellite bus used for RazakSAT was jointly developed by ATSB and Satrec Initiative, a commercial satellite manufacturer in Korea. Satrec Initiative markets the bus system as the "SI-200".
13rd lecture: 30/8/09
Mesh Topology & Tree Topology
Mesh Topology
A type of network setup where each of the computers and network devices are interconnected with one another, allowing for most transmissions to be distributed, even if one of the connections go down. This type of topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this type of topology is commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology.
Mesh Topology
A type of network setup where each of the computers and network devices are interconnected with one another, allowing for most transmissions to be distributed, even if one of the connections go down. This type of topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this type of topology is commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology.
The Mesh topology gives rise to more efficient message propagation, and means that alternative routes can be found if a link fails or there is congestion. A “route discovery” feature is provided which allows the network to find the best available route for a message.
Tree Topology
A Tree topology consists of a Co-ordinator, to which other nodes are connected as follows:
- The Co-ordinator is linked to a set of Routers and End Devices - its children.
- A Router may then be linked to more Routers and End Devices - its children. This can continue to a number of levels.
This hierarchy can be visualised as a tree structure with the Co-ordinator at the top, as illustrated in the diagram below.
A Router can be used in place of an End Device in a Tree network, but the message relay functionality of the Router will not be used -only its applications will be relevant.
Structural Rules
The structural rules and terminology of the Tree topology are as follows:
- The Co-ordinator and Routers can have children, and can therefore be parents.
- End Devices cannot have children, and therefore cannot be parents.
Communication Rules
The communication rules in a Tree topology are as follows:
- A child can only directly communicate with its parent (and with no other node).
- A parent can only directly communicate with its children and with its own parent.
- In sending a message from one node to another, the message must travel from the source node up the tree to the nearest common ancestor and then down the tree to the destination node.
12nd lecture: 26/8/09
Coaxial cable
Coaxial cable, or coax, is an electrical cable with an inner conductor surrounded by a tubular insulating layer typically of a flexible material with a high dielectric constant, all of which are surrounded by a conductive layer (typically of fine woven wire for flexibility, or of a thin metallic foil), and finally covered with a thin insulating layer on the outside. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, who first patented the design in 1880.
Coaxial cable is used as a transmission line for radio frequency signals, in applications such as connecting radio transmitters and receivers with their antennas, computer network (Internet) connections, and distributing cable television signals. One advantage of coax over other types of transmission line is that in an ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other transmission lines, and provides protection of the signal from external electromagnetic interference.
Coaxial cable should not be confused with other shielded cable used for carrying lower frequency signals such as audio signals. Shielded cable is similar in that it consists of a central wire or wires surrounded by a tubular shield conductor, but it is not constructed with the precise conductor spacing needed to function efficiently as a radio frequency transmission line.
Coaxial cable, or coax, is an electrical cable with an inner conductor surrounded by a tubular insulating layer typically of a flexible material with a high dielectric constant, all of which are surrounded by a conductive layer (typically of fine woven wire for flexibility, or of a thin metallic foil), and finally covered with a thin insulating layer on the outside. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, who first patented the design in 1880.
Coaxial cable is used as a transmission line for radio frequency signals, in applications such as connecting radio transmitters and receivers with their antennas, computer network (Internet) connections, and distributing cable television signals. One advantage of coax over other types of transmission line is that in an ideal coaxial cable the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other transmission lines, and provides protection of the signal from external electromagnetic interference.
Coaxial cable should not be confused with other shielded cable used for carrying lower frequency signals such as audio signals. Shielded cable is similar in that it consists of a central wire or wires surrounded by a tubular shield conductor, but it is not constructed with the precise conductor spacing needed to function efficiently as a radio frequency transmission line.
Twisted pair
Twisted pair cabling is a form of wiring in which two conductors (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources; for instance, electromagnetic radiation from Unshielded Twisted Pair (UTP) cables, and crosstalk between neighboring pairs.
UTP
STP
Fiber Optic
A fiber optic cable transmits a signal using a wave of light, while copper wires transmit a signal using an electric current. (Palais, 1998). A typical fiber optic wire consists of a plastic sheath surrounding a glass tube. Inside the tube is a tiny core in which the light waves travel. Separating the core and the tube is a cladding that prevents the light waves from escaping. One wire design has a core diameter of 125 microns and a sheath diameter of 2.5 millimeters.
The wire’s small size provides an advantage over copper wires. Fiber optic cables weigh less than copper wires, which makes installation easier and allows the wires to be placed in smaller areas. (Palais, 1998). Although the wires are made of glass, they are extremely flexible therefore easing the problems involved with installation.
Although the core of a fiber optic cable is very small, large amounts of information can be transported at one time. In copper wires, only one signal can be sent across the wire at a single time but in a fiber optic cable, many light waves can be sent at once. This allows the wires to be more cost effective. Silicon oxide is the material used to make fiber optic wires. This material is less expensive than the copper used in coaxial cables making fiber optics less expensive to make. Also, fewer fiber optic cables are needed for mass communication.
Fiber optic cables also have disadvantages. Because they use light to transmit information they are incompatible with the old copper wires. This creates a problem because telephone companies cannot use the wire system that is already present. They must build a new system using fiber optics. Fiber optic cables are also very difficult to connect. In order to connect the wires, the glass tube must be broken and then melted together with the new wire. With copper wires, you simply cut away the plastic coating and join the wires. This also creates a problem when repairing fiber optic wires. A copper wire is much easier to repair than a fiber optic wire. Special tools and highly trained professionals are needed to repair the damaged fiber wires.
In a fiber optic cable, many light waves of information are transmitted at one time. Sometimes so much information comes in that the cable becomes jammed and the information slows down. This cannot occur in copper wires because only one signal is generated at a time. Often, at points in the cable where traffic is heavy, bottlenecks occur. A bottleneck is when so much information tries to squeeze through but is lost.
11st lecture: 23/8/09
Today is 1st day we go class after mid-term break. Today is a raining day, browsing internet is fun, but learning the technical terminologies such as http, path and etc. is really torturing, especially in this raining morning. Anyway, I also have learning some new information about internet from this lecturer. I felt that sometime I had got some wrong information if I didn’t learn this topic at this class. The lecture today end quite fast today, so I have time 2 take my lunch before the coming class because my lecture today is until 5pm.
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