vprašanja

Imam nekaj vprašanj, če mi lahko kdo pomaga.
Kaj kodiramo s kodo ASCII?
Koliko znakov predpisuje osnovna koda ASCII?
Katere pisne znake upošteva koda ASCII?
Kaj je slabost kode ASCII?
Kaj so kodne tabele?
Koliko operacij na sekundo izvrši procesor?
Kakšen je princip delovanja laserske plošče?

Kdor mi bo odgovoril, se mu najlepše zahvaljujem!

Lep pozdrav

Maja

No, Maja, malo se pa le sama potrudi….
Upam da ni ves tvoj trud samo zastavljena vprašanaja, pol pa “plonkanje”…

Malo ti bomo vseeno pomagali, nekaj o ascii poglej na

1. ASCII – The American Standard Code for Information Interchange is a standard seven-bit code that was proposed by ANSI in 1963, and finalized in 1968.
Computers can only understand numbers, so an ASCII code is the numerical representation of a character such as ‘a’ or ‘@’ or an action of some sort.
ASCII was developed a long time ago for use with teletypes and so the descriptions are somewhat obscure. If someone says they want your CV however in ASCII format, all this means is they want ‘plain’ text with no formatting such as tabs, bold or underscoring – the raw format that any computer can understand. This is usually so they can easily import the file into their own applications without issues. Notepad.exe creates ASCII text, or in MS Word you can save a file as ‘text only’
ASCII was established to achieve compatibility between various types of data processing equipment. Later-day standards that document ASCII include ISO-14962-1997 and ANSI-X3.4-1986(R1997)

2. 128 decimal numbers. The Extended ASCII Character Set also consists of 128 decimal numbers and ranges from 128 through 255 representing additional special, mathematical, graphic, and foreign characters.

3. glej tabelo

4. ASCII uses only 7 bits. The only languages that can comfortably be written with the repertoire of US-ASCII happen to be Latin, Swahili, Hawaiian and American English without most typographic frills. It is rumoured that there are more languages in the world.

5. numerical representation of a character

6. odvisno od tipa procesorja, lahko tudi do nekaj milijonov na sec.

7. CDs (and DVDs) rely on laser technology to read (and write) the data on discs. The word LASER stands for Light Amplification by Stimulated Emission of Radiation. Lasers generate coherent light, ie light comprising photons with the same wavelength and in-phase. This allows the light beam to be focused to a very small spot size similar to the actual wavelength of the light itself. The advent of lasers and in particular low cost laser emitting diodes has allowed the compact disc technology to become one of the most successful consumer electronic technologies of all time.
In the late 60s, Philips developed the laser video disc, the first such application of the laser for a consumer electronics product. The 30cm disc was capable of storing up to 60mins of analogue video per side. A low power laser was used to read the video information stored in pits in the disc surface. The video and audio signals are represented in analogue form by these pits which were arranged in a spiral pattern, like vinyl records.
CD players use light emitting diode lasers, which are compact and low cost, to read the data contained in pits in the surface of the disc. CDs require an infra red laser, while the newer DVDs require a red laser for the smaller pit geometry.
The laser diode is mounted on a swivel arm which can be moved radially to follow the pits up and down to keep them in focus. A semi-reflective mirror allows the reflected light to pass back to a photo detector. When the laser beam falls on a pit very little is reflected. The changing light pattern detected is then converted into a series of zeros and ones which are then decoded into the original audio or computer data signal.
The main difference between CDs and laserdiscs (apart from the size of disc) is that the CD uses a digital technique where the pits indicate whether a data bit is ‘0’ or ‘1’. Also laserdiscs can be either CAV (Constant Angular Velocity) or CLV (Constant Linear Velocity), but all CDs use CLV. This means that the pit sizes do not vary from inside to outside of the disc but the angular velocity does vary.
More info and CD Formats: