Sistem Dual Tone Multiple Frequency (DTMF) Pada Pesawat Telepon

Sistem Dual Tone Multiple Frequency (DTMF) adalah Piranti Semikonduktor yang dirancang untuk digunakan pada sistem dial pada pesawat telepon. DTMF membangkitkan suatu sinyal nada yang merupakan kombinasi dari 2 buah nada yang memiliki frekuensi rendah dan frekuensi tinggi. Kelompok frekuensi rendah meliputi 697 Hz, 770 Hz, 852 Hz, dan 941 Hz. Sedangkan kelompok frekuensi tinggi meliputi frekuensi 1209 Hz, 1336 Hz, 1477 Hz, dan 1633 Hz. Kombinasi dari kelompok frekuensi rendah dengan frekuensi tinggi yang saling berpasang pasangan membentuk 16 macam kombinasi pasangan nada sinyal DTMF yang standard.

Alat pengirim kode DTMF merupakan 8 rangkaian oscilator yang masing – masing membangkitkan frekuensi pada tabel diatas. Selain itu ada rangkaian pencampur frekuensi untuk mengirimkan 2 nada yang terpilih. Sedangkan untuk penerima kode DTMF lebih rumit. Penerima dibentuk dari 8 buah filter yang tidak sederhana dan rangkaian tambahan lainnya.

Pada penelitian sebelumnya (Sunarno, 2003) DTMF dapat dinyatakan langsung dalam data biner. DTMF dapat mengirimkan sinyal per 4 bit yang dikirimkan dalam bentuk kombinasi 2 nada. Sebagai contoh jika men-dial angka 4 maka keluar kombinasi frekuensi dari dua buah kelompok frekuensi, rendah dan tinggi yaitu frekuensi 770 Hz dan 1209 Hz. Dari kombinasi frekuensi tersebut akan membangkitkan kombinasi biner 0100.

Prinsip Kerja DTMF :
Setelah beralih ke Teknologi Digital, cara meminta nomor sambungan telepon tidak lagi dengan cara memutar piringan angka tapi dengan cara memencet tombol-tombol angka. Cara ini dikenal sebagai Touch Tone Dialing, sering juga disebut sebagai DTMF (Dual Tone Multiple Frequency).

Dual Tone Multiple Frequency (DTMF) adalah teknik mengirimkan angka-angka pembentuk nomor telpon yang di-kode-kan dengan 2 nada yang dipilih dari 8 buah frekuensi yang sudah ditentukan. 8 frekuensi tersebut adalah 697 Hz, 770 Hz, 852 Hz, 941 Hz, 1209 Hz, 1336 Hz, 1477 Hz dan 1633 Hz, seperti terlihat dalam Gambar 1 angka 1 di-kode-kan dengan 697 Hz dan 1209 Hz, angka 9 di-kode-kan dengan 852 Hz dan 1477 Hz. Kombinasi dari 8 frekuensi tersebut bisa dipakai untuk meng-kode-kan 16 tanda, tapi pada pesawat telepon biasanya tombol 'A' 'B' 'C' dan 'D' tidak dipakai.

Kombinasi Nada DTMF
Teknik DTMF meskipun mempunyai banyak keunggulan dibanding dengan cara memutar piringan angka, tapi secara tehnis lebih sulit diselesaikan. Alat pengirim kode DTMF merupakan 8 rangkaian oscilator yang masing-masing membangkitkan frekuensi "aneh" di atas, ditambah dengan rangkaian pencampur frekuensi untuk mengirimkan 2 nada yang terpilih. Sedangkan penerima kode DTMF lebih rumit lagi, dibentuk dari 8 buah filter yang tidak sederhana dan rangkaian tambahan lainnya.

Beberapa pabrik membuat IC khusus untuk keperluan DTMF, diantaranya yang banyak dijumpai adalah MC145436 buatan Motorola, MT8870, MT8880 dan MT8888 buatan Mitel Semiconductor. MC145436 dan MT8870 merupakan penerima DTMF, menerima sinyal dari saluran telepon kalau ternyata sinyal yang diterima tadi merupakan kombinasi nada yang sesuai dengan ketentuan DTMF, mengeluarkan kode biner sesuai dengan kombinasi nada tersebut. MT8880 dan MT8888 merupakan penerima dan pengirim DTMF, selain bisa berfungsi sebagai penerima DTMF, bisa pula dipakai untuk membangkitkan nada DTMF sesuai dengan angka biner yang diterimanya.

Saluran data (Data bus) dan sinyal-sinyal kontrol MT8880 dirancang sesuai dengan karakteristik mikrokontroler buatan Motorola (misalnya MC68HC11), sedangkan MT8888 disesuaikan dengan mikrokontroler buatan Intel (termasuk AT80C51). Tapi untuk AT89C2051 yang memang tidak punya saluran data (data bus) perbedaan kedua IC itu tidak ada artinya, mengingat saluran data dan sinyal kontrolnya disimulasikan lewat program yang diterimanya.

Technology Hubble Telescope to study the atmosphere

A Telescope for the first time succeeded in taking thousands of pictures of galaxies and nebulae within a few million light years from the Milky Way so clearly. The telescope was launched into orbit from the space shuttle Discovery in 1990. Hubble Telescope materialized from a dream man to put telescopes in space. Problems with the atmosphere during this arise can be resolved by the Hubble Telescope and of course the view from the eyes of the Hubble Telescope is much cleaner and better. At the time the project is considered ridiculous and waste of money. 

Some Astronomical community reject the presence of the Hubble Telescope. As time goes everything has changed, no doubt contributed Hubble astronomers a pedestal. 20 years is not a short time to the Hubble telescope, but it's 20 years more people get a chance to see the beautiful and magnificent, vast universe from the eyes of the Hubble Telescope.

History of Hubble 

In 1962, the U.S. National Academy of Sciences or the National Academies of Science recommends of building a giant space telescope. Three years later, in 1977, Congress began Collect funds for the project. In the same year, making the Hubble space telescope to begin. 

For over 12 years the originator of shelf space telescope is rugged seek funding from the NASA funding. Responses were obtained, much better build 20 ground-based telescopes than building teleksop space will only cause problems and just dream of science fiction fans. No one wants to think about the advantages of a shelf space telescope that could solve the problem of the atmosphere. 

After going through a long, secured funding. The Independent Space Telescope Science Institute in Baltimore was formed in 1983 to carry out scientific research operations at the same time to get the data for researchers. 

Hubble telescope construction, was completed in 1985. Hubble di'angkasakan 'for the first time on 25 April 1990. In fact, Hubble is planned to begin operation in 1986. Hubble sends blurry images and indistinct. NASA eventually discovered that the telescope lens shift as much as 1/50 the thickness of a human hair! In December 1993, the Space Shuttle Endeavor, Hubble is sent to modify by adding a new camera to fix the error on the primary lens.

Size of the Hubble Telescope 

Telescopes : The thickness reaches 13.1 meters (43.5 feet) in diameter 4:27 meters (14.0 feet) and weighs 11.000 kilograms. Hubble size is almost the same as a school bus. Also, notice that there is the orange tube telescopes. This is the power source Hubble.

Lens 

Lens Primer Hubble telescope, measuring 2.4 m (8 feet) and weighing up to 826 pounds. The lens is made of silica glass coated with a thin layer of pure aluminum to reflect light. In addition to aluminum coating, the lens also has a useful layer of magnesium fluoride to prevent oxidation and ultraviolet light (UV) from the sun so that the lens is not quickly broken.

How it Works 

First of all, Hubble captures images, once received by the telescope, the image will be changed manjadi digital code and radiated to earth using mamiliki antennas transmit capability of 1 million bits per second. Once the code is digitally signed by the earth station, the code will be converted into images and spectrograph (an instrument used to record the spectrum of astronomical). 

The telescope is able to run 5 miles per second. Hubble can get around more than 150 million miles per year (± 241 million kilometers)!

Hubble Telescope Control and Operation 

The telescope is controlled from the Goddard Space Flight Center in Greenbelt, Md. New problems arose in the mirror whose shape does not fit with the side edges so that the first Hubble images look blurry. Successfully launched new telescope this does not mean instant success. While the image is still much better than the photo shoot of the Earth, but the blurring of the image caused only 20% of the image in the center of the focus. The algorithm was created to solve the problem, but another problem arises from the solar wind as the Hubble telescope orbits from the light side to the dark side in every orbit. As a result, the media was quick to react by stating that the instrument is "techno-tukey".

Repair Hubble Telescope 

Hubble Telescope has experienced four times the improvement made by the astronauts delivered by the shuttle. The first repair mission in December 1993, the optical Hubble also increased and the resulting image sharper and is designed fokus.Teleskop will get repairs and checks periodically and there is no limit to the time when Hubble is no longer able to work. Hubble Telescope is currently no longer a first telescope was launched. Currently, the Hubble telescope has been far greater than that released in 1990. At least 60 times better.

Task Hubble Telescope 

Hubble Telescope ability to look far into the past history of the universe and see its evolution is a very basic knowledge of a given Hubble to human history. Hubble telescope too, who showed for the first time face a different universe from the universe close (around us that telrihat from Earth) as we know it. Hubble telescope successfully provide evidence the universe is expanding very rapidly changing paradigms of scientists that the universe is expanding slowly. This evidence comes from observations of a supernova, the explosion of massive stars end that would end his life. 

Light from the supernova Hubble Telescope captured came from a great distance yag never predictable. And this is the evidence of an acceleration in the expansion of the universe. Even the discovery of a major discovery in physics since quantum physics and general relativity. In 2006, Hubble returned to prove the existence of dark matter and shelf space telescope is also used to show the relationship between the size of the black hole and the size of the location of the galactic black hole. 

Hubble telescope is also used in a project aimed at a close look at the stars, which were observed Orion nebula and planet formation area around the young star. Even protoplanet around the young star, was arrested by Teleskp been able to Hubble. The image was taken with the incredible resolution that can not be produced by ground-based telescopes. Hubble with other space telescopes such as the Chandra X-ray Observatory and the Spitzer space telescope working at infrared wavelengths, they complement each other and produce fot the effects and colors are amazingly beautiful.

The future of the Hubble Telescope 

Hubble Telescope in the period 2003 to 2006 had experienced a period of uncertainty about the future. Last repair mission in 2004 was canceled by NASA administrator, Sean O'Keefe. Mission re-run as successor to the Hubble O'Keefe, Mike Griffin replaced in 2006. And the service was conducted in May 2009. Hubble also Toward Supernova? 

Besides all trips Hubble Telescope, Hubble results given can not be ignored. Hubble telescope it brings great success in the world of astronomy to open the universe and the processes therein. Hubble Telescope is more important telescope in history after Galileo's first telescope 400 years ago. 

Hubble Telescope future was already determined until the end of April 2013. Or in other words the Hubble Telescope will still be in operation at least three years. After that there will be no mission to serve and regular batteries, solar panels and pointing telskop engine will start to weaken and fail. Until 2013, the Hubble Telescope and the entire instrument (the Advanced Camera for Surveys, the Cosmic Origins Spectrograph, Fine Guidance Sensors, Near Infrared Camera and Multi-Object Spectrometer, Space Telescope Imaging Spectrograph and the Wide Field Camera) will remain in good condition. 

All instruments will still work fine at least 5 more years. And when the fate of the Hubble Telescope will be close to the end of his duty, he will still use the rest of his tenure with the maximum ability to provide information that reveals the mysteries of the universe in which he recorded a beautiful image. Task Hubble will be forwarded by the James Webb Space Telescope to be launched in 2014.

Dyson Air Multiplier Fan Without Propeller

On October 18, 2009, James Dyson released a new product called the Dyson Air Multiplier. Designed to replace the small fan on the table or a big fan, Air Multipiler intended to provide smoother airflow and work in a way that is safer than similar products. The idea for the Air Multiplier came from a previous Dyson invention, Airblade hand dryer.

Fluid dynamics of an engineer working on the design to realize that a large amount of air retained in the hair, and decided to utilize it for other purposes. The fan is working with air in through the inlet in the base pillar before it is pressed out through the outlet in the ring. Jet air delivered through a ring aerofoil shape, creating local low pressure, so it pulls air from behind because it decelerates in a process known as inducement, property Coanda effect. After that force air out in front and side pushed forward join. With this process, a small brush impeller fan base can power an air hole far greater without using fast fan blades. Makers boost air at the bottom do not really have a bar, but the propeller.

   

Design For a nearly identical bladeless fan, has been patented by Tokyo Shibaura Electric in 1981, but never produced. Initial patent claim by Dyson was rejected by the Intellectual Property Office, decided that it "can not be considered novel or can not be considered to involve an inventive step" compared to the Japanese version. A subsequent patent application from Dyson highlights improvements aerodynamics. 

How it Works :

Secret Thermos or Vacuum Bottle For Water Heating

Gbr. Thermos (Vacuum Bottle) or Flask

A Brief History About Thermos or Vacuum Bottle Termos or also known as a vacuum bottlr was invented by Sir James Dewar. He worked as a lecturer at the Royal Veterinary College, cuman not teach doang loo, he also made some research. Well when he examines the electrical resistance accidentally discovered vacuum tubes used for shipping and storage of liquid gas.

But Dewar saw another opportunity of discovery. Then he developed the vacuum tube to a flask that is capable of maintaining the temperature, cold or hot.

According to the Theory of Exchange of Henry Prevost Babbage (1824 - 1918) that a cooler is always absorbs the heat waves from the object to the other until both have the same temperature. Based on this theory it is hot or cold tea in a thermos will lose heat or absorb heat from its place. However, the flasks are designed to be inhibiting ketida how heat can be transferred: conduction, convection, and radiation.

Gbr. James Dewar

Flasks made ​​of glass-walled duplex, Naah between the wall and the vacuum created one wall is lined with a shiny layer (here we use silver). In the flask there are two walls of glass, each of which is made shiny. The inside is shiny so that the heat from the hot water is not absorbed by the wall. While the outside walls are made of glass polished and coated with silver, aim to prevent heat transfer by radiation. Vacuum is used here to prevent heat transfer by convection. Close the flask was not functioning? Obviously there dong, the cap is made of insulating material here, useful for preventing heat transfer by conduction. Thermos Structure Along The explanation. 

Gbr. Structure Flask

Description : 

Close Stopper Thermos = Prevent conduction heat transfer. Wall In Glass = Prevent heat transfer from the hot water that is not absorbed by the wall. 

Outer Wall Glass = Prevent heat transfer by radiation. Space Vacuum (Vacuum) = Limiting the possibility of heat lost from or enter into the flask with convection. 

Wall Pelingdung Glass = As an insulator between the glass tube with the surrounding air. 

Retaining Rubber Glass = Maintain position bottles (glass) remain in place. 

Explanation : 

Thermos is one of the tools used to prevent the occurrence of conduction, convection, and radiation. So that the water we save will remain hot and we can use when we need. Well, the secret so that events apasih conduction, convection, and radiation can be prevented? The secret is in the inside of a thermos, it turns the material is made of a shiny material, such as silver. Shiny material is intended that the radiation delivered by water bounces back and not out of the flask. Meanwhile, if we look at the middle turns in the middle of the vacuum created intentional so it would minimize the possibility of conduction and convection. Since there is no medium in the vacuum, the event that is used by people to make and keep the water in a thermos flask keep hot. 

Things to note in this flask is 

1. The existence of a vacuum chamber is limited by the glass on one of the layers dilapisin by a shiny layer. 

2. Thermos berprinsipkan on the use of materials that inhibit adiabatic heat exchange by conduction, convection, and radiation. 

Adiabatic gas is change in circumstances in which no heat in or out of the system. 

Conduction is the transfer of heat transfer that does not diserai constituent particles of matter, and cuman occur in solids. 

Convection is the transfer of heat transfer with constituent particles of matter, and occurs in liquids and gases. Radiation is the transfer of heat without the required medium as the intermediary.

Unmanned Aerial Vehicle Aircraft Technology Made in Indonesia

Unmanned aircraft (Puna) has a very small size, with a wingspan of less than 4 meters. However, its role will be very large, especially keeping the defense of the territory of the Republic of Indonesia enemy alien ships trying to enter, and also against the terrorists.

Kestrel and Sriti is a product made in Indonesia, not imported. Puna Sriti type is perfect for the needs of tactical forces or types of short range, while Alap-alap for surveillance and reconnaissance operations.

Head of the Agency for the Assessment and Application of Technology (BPPT) Marzan A. Iskandar said it immediately produces drone. Not just a prototype. "Right now we are finalizing it for the benefit of reconnaissance aircraft and operations," he said after awarding BJ Habibie Technology Award 2012 in the Hall of BPPT, Jakarta, Wednesday, September 12, 2012.

There are at least two benefits of unmanned aircraft made in Indonesia. For defense purposes, one of which oversees foreign ships that are in Indonesia, also for civilian purposes. "In the past, these aircraft are used to support the creation of artificial rain," said Marzan.

In September it will be tested in conjunction with the Ministry of Defence. "Tests conducted at Halim Perdanakusuma sense. Having decided that the new production and how many needs," she said.

Unmanned aircraft developed by BPPT actually already appeared in five variants. Three is a type of UAV aircraft for mapping surveys while two variants for defense. This aircraft will be used by the Defense Department and the military.

Besides Alap-alap and Sriti, previously woodpecker, Wulung, and Crow. Wulung suitable for monitoring high altitude missions. Among other things, shooting air at a very wide area, measurement characteristics of the atmosphere, and monitoring of leakage power at high voltage power line.

Meanwhile, Crow suitable for aerial photography missions in wide range. And trigger suitable for aerial photography missions on a small area, close surveillance of a target, forest monitoring, monitoring of sea and beach.

Specification

Like what unmanned reconnaissance aircraft made in Indonesia? BPPT explained, drone made in Indonesia would be designed with the concept of autopilot and autonomous. This aircraft is moved automatically through the control of the Ground Control System (GCS).

"So keep it under control, the plane can not go anywhere, according to the control program at GCS," said Agus Suprianto, engineering staff Work Unit Industrial Technology Center Deputy Defence Industrial Technology and Engineering Design Build BPPT in Jakarta, Wednesday, September 12, 2012.

For Alap-Alap Double Boom and Sriti, both physically smaller than the drone for the benefit of other mapping survey. The ability to fly its maximum height is also lower than the survey aircraft observations.

"Reconnaissance aircraft capable of flying 7,000 feet, in order to more clearly focus on improving the performance of surveillance, illegal logging piracy, hijacking ships, so much to the defense technology," said Agus. And certainly not noisy and attract attention.

For photographing objects of surveillance, the aircraft is equipped with a specially-made video camera SONY. These cameras weighing up to 9 kg, according to Agus, has better quality than the usual camera and professional camera.

He continued, the aircraft will be able to conduct reconnaissance in the air after climbing process. "So the stage, after take off, the climbing, well after the new aircraft surveillance can record objects. During the motion of objects can be observed," he said.

As for sending data surveillance, the two aircraft is equipped with a sensor that is directly connected to the GCS on the mainland. Meanwhile, the data is real time, can be directly processed at the control center.

"This is a pioneering generation, the first generation of unmanned aircraft in Indonesia," he said. This particular aircraft will be used by the Ministry of Defense and Armed Forces. "It is adjustable, the smaller more agile," said Agus.

Matters drone had been a lively debate in early 2012. Related discourse MoD bought four drone of Kital Philippine Corporation (KPC). Reconnaissance aircraft combines machine from Italy, the infrastructure of the Philippines, and technology from Israel.

The discourse was opposition from Members of Parliament, one member of Commission I of the House of Gerindra, Ahmad Muzani asking drone purchase plan was canceled because Indonesia has been able to have a similar product. "Even bought neighboring countries like Malaysia," he said at the Parliament Building, Jakarta, Monday, March 26, 2012.

Alap-Alap Specifications Double Boom

Wing span: 3.510 m

Configuration: inverted v-tail boom and double high wibng

Empty weight: 8.5 Kg

Payload weight: 2.5 Kg

Maximum take off weight, MTOW: 18 Kg

Cruising speed: 55 Knots

Long fly: 5 Km

Flying range: 140 Km

Maximum flying height: 7,000 feet

Sriti Specifications

Wing span: 2.988 m

Configuration: flying wing

Empty weight: 6 Kg

Payload weight: 2 Kg

Maximum Take Off Weight, MTOW: 8.5 Kg

Cruising speed: 30 Knots

Long flight: 1 hour

Flying range: 5 Nautical mile

Maximum flying height: 3,000 feet