assigment osiloskope

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PENGENALAN KEPADA OSILOSKOP Osiloskop adalah alat asas untuk mengkaji berbagai jenis bentuk gelombang . Ia boleh digunakan untuk mengukur kuantiti seperti voltan puncak , frekuensi , beza fasa , lebar denyut,masa lengah , masa naik dan masa jatuh . Terdapat berbagai jenis osiloskop daripada alatan asas yang mudah kepada alatan boleh aturcara yang canggih dengan bacaan digit . Walau bagaimanapun,prinsip dan ciri-ciri asasnya tetap sama KEGUNAAN OSILOSKOP * Pengukuran Voltan Puncak-ke-puncak Amplitud puncak ke puncak bentuk gelombang yang terpapar pada osiloskop bolehdiukur dengan mudah . Pastikan bahawa tombol vernier pusat pada kawalan VOLT/DIV pada kedudukan tentukur (CAL) sebelum mengukur amplitud bentuk gelombang . Vpp = (jumlah bahagian p ke p ) x ( volt/div ) Voltan Puncak , Vp = Vpp / 2 * Penentuan Frekuensi Tempoh ialah masa yang dilalui oleh satu kitar gelombang . Tempoh masa T boleh ditentukan dengan mengukur masa bagi satu kitar mengikut bahagian mendatar dan mendarab nilai tersebut dengan nilai time/div yang disetkan pada osiloskop . T = ( jumlah bahagian mendatar/kitar ) ( time/div ) - Frekuensi dikira sebagai songsangan tempoh masa , T .

* Pengukuran Arus Osiloskop merupakan alatan bergalangan masukan tinggi . Oleh itu , ia tidak boleh digunakan secara langsung untuk mengukur arus . Arus diukur melalui jatuhan voltan pada satu perintang . Untuk tujuan itu , perlu berhati-hati dengan sambungan osiloskop kepada perintang kerana salah satu hujung perintang perlu berada pada keupayaan bumi kecuali jika penguat masukan kebezaan digunakan . * Pengukuran Fasa * Pengukuran DenyutOPERASI OSILOSKOP * Alur elektron bergerak dan menghentam lapisan fosfor di skrin . * Satu titik terbentuk di seluruh skrin dan kecerahannya ditentukan oleh banyaknya electron yang terkena pada lapisan fosfor . * Alur elektron dipesong pada paksi-x dan paksi-y untuk mempamerkan bentuk 2 dimensi pada skrin . * Paksi-x dipesong dengan satu kadar malar yang dirujuk kepada masa ( time/div ) . * Paksi-y dipesong sebagai sambutan kepada masukan yang diberkan ( volt/div ).

PRINSIP KENDALIAN * Osiloskop terdiri daripada tabung sinar katod (C.R.T.) dan litar-litar kawalan dan masukan yang berkaitan . * Dalam tabung sinar katod , elektron terjana oleh katod yang dipanaskan dibentukkan kepada alur halus dan dipecutkan ke arah skrin pendarflour . * Skrin tersebut mengeluarkan cahaya pada tempat yang terkena elektron . * Alur elektron terpesong pada arah menegak dan mengufuk oleh voltan yang dikenakan pada plat memesong .

BINAAN OSILOSKOP

ALAT-ALAT KAWALAN PADA OSILOSKOP Litar Tegak * Volt/div - Memberikan skala yang tertentu pada gambaran isyarat di paksi-Y . - Kalau isyarat terlalu besar , skala dinaikkan dan sebaliknya . * Pembolehubah - Jika skala Volt/div hendak digunakan ianya mesti dipusingkan ke kedudukan CAL , sekiranya tidak dilakukan nilai yang ditunjukkan bukanlah nilai yang sebenar . * AC-GND-DC - GND . membumikan isyarat supaya garis sifar dapat ditentukan di skrin . - AC . memberikan gambaran isyarat ulang-alik . - DC . memberikan isyarat terus . * Position - membolehkan isyarat dinaikkan dan diturunkan di skrin . * INV - Menyongsangkan isyarat .

Litar Mendatar * Time/div - memberikan skala masa isyarat dari kiri ke kanan skrin osiloskop . - skala hanya boleh digunakan jika pembolehubah di bahagian tengah berada pada kedudukan CAL . * Position - Membolehkan isyarat dibawa ke kiri atau ke kanan skrin osiloskop .

Litar Picu * Trigger Source - INT . isyarat diambil dari dalam ( salah satu bentuk gelombang atau isyarat masukan ) - EXT . isyarat diambil dari luar ( perlu masukan pada punca EXT TRIGGER ) - LINE . isyarat diambil dari talian atau frekuensi kuasa a.u. * SYNC ( Penyegerakan ) - Selalu digunakan dalam keadaan biasa ( normal ) - Kedudukan TV digunakan jika bentuk gelombang adalah kompleks . * Trigger Level ( aras picuan ) - menjana gelombang mata gergaji yang diperlukan oleh plat pesongan datar jika mod ' Time ' digunakan ( asas masa ) . - Penguat datar menguatkan isyarat tadi sebelum dihantar ke plat pesongan datar pada CRT * Litar Picu - Mengawal pergerakan antara isyarat mata gergaji dan isyarat masukan yang diberikan pada litar tegak . - Memastikan pesongan tegak dan datar bermula pada masa yang sama . - Boleh disambungkan kepada ' internal ', ' external ' dan ' line ' . * Bekalan Kuasa - Membekalkan voltan tinggi kepada CRT . - Membekalkan voltan kendalian kepada lain-lain litar .

Skrin * Focus - Memfokuskan paparan kepada garisan yang lebih halus . * Intensity - Mengawal kecerahan paparan . * Beam Finder - Untuk mendapatkan semula paparan yang teranjak keluar dari skrin . * Power On/Off - Menghidup atau mematikan osiloskop .

MULTICHANNEL OCILOSCOPEAll TiePie engineering measuring instruments can be used as a USB oscilloscope. An oscilloscope is an instrument to display signal voltages, plotted against time (Yt) or against another signal voltage (XY). A benefit of graphically showing signals is that an oscilloscope will show what is actually happening. The precise shape of the signal and time relations in the signal or between signals can be seen.

WHEN TO USE THE OSCILOSCOPEA scope has many applications, in many different areas. An important application of the oscilloscope is to troubleshoot circuits that do not function properly. Another possible application is using the labscope as signal monitor when adjusting a circuit under test. An instrument toolbar is created for each detected instrument. The instrument toolbar is fully configurable through the program settings. It shows the current settings of the instrument and allows to change all settings.

USING THE INSTRUMENTS TOOLBAR

In the default setup, the instrument toolbar contains the following items:Start/Stop button

The Start button is used to start continuous measurements. When the measurement is running, it will change into a Stop button to stop the running measurement.

Both actions can also be executed by hotkey S.One shot button

When no measurement is running, the One shot button is enabled. It can be used start a single shot measurement (hotkey O).

Auto setup button

The Auto setup button can be used to let the software quickly change several instrument settings, to acquire stable measurements. Use it by clicking the button or pressing its hotkey Q (quick auto setup). When the CTRL key is pressed while starting the auto setup, the instrument will stay in auto setup mode. This can be used to track changing signals. Choose which instrument settings may be changed by auto setup in Settings->Instruments->Auto setup.

Measure mode button

The measure mode button can be used to switch between block- and streaming mode. Switching the measure mode requires the instrument to be stopped measuring.

Instrument identification

This item displays the instrument name as well as its serial number, which is a unique number in your measuring instrument. By using the serial numbers as the instrument ID, it is clear which of the instruments you are controlling. Clicking the instrument ID will show a popup menu with all instrument settings.

Record length + Sample frequency + Resolution

In this item, information concerning the current sample frequency, record length and the resolution is shown. Settings can be adjusted through popup menus by clicking on the text labels.

Time out + Trigger source

When using an instrument that supports triggering, the trigger timeout and trigger source of the measuring instrument are also shown. Settings can be adjusted through popup menus by clicking on the text labels.

Presamples knob

The pre samples turning knob controls the pre and post samples ratio. By default, no pre samples are used and it is set to 0%. Dragging it up and down adjusts the knob, a hovering readout displays the current setting. Right clicking it shows a popup menu with predefined settings and a user defined setting. Other controls that can be placed on the instrument toolbar are:

Sample frequency

The sample frequency readout shows the current sampling frequency. Clicking the readout shows a popup menu with available sample frequencies.

Increase/decrease sampling frequency

Two buttons are available to increase or decrease the sample frequency:

Decrease the sample frequency one step (hotkey F3). Increase the sample frequency one step (hotkey F4).

The steps that are taken are the sample frequencies that are available in the sample frequency menu of the instrument. When a user defined sample frequency was selected, each subsequent click on one of these buttons will double or halve the sample frequency.

Record length

The record length readout shows the current record length. Clicking the readout shows a popup menu with available record lengths.

Increase/decrease record length

Two buttons are available to increase or decrease the record length:

Decrease the record length one step (hotkey F11). Increase the record length one step (hotkey F12).

The steps that are taken are the record lengths that are available in the record length menu of the instrument. When a user defined record length was selected, each subsequent click on one of these buttons will double or half the record length.

Resolution

The resolution readout shows the current resolution. Clicking the readout shows a popup menu with available resolutions.

Increase/decrease resolution

Two buttons are available to increase or decrease the resolution:

Decrease the resolution one step. Increase the resolution one step.

The steps that are taken are the resolutions that are available in the resolution menu of the instrument.

Increase/decrease pre trigger percentage

Two buttons are available to increase or decrease the pre trigger percentage:

Decrease the pre trigger percentage with 2.5% (hotkey SHIFT + ) Increase the pre trigger percentage with 2.5% (hotkey SHIFT + )

Oscilloscope time/div

The oscilloscope time/div readout shows the current time/div setting as if the instrument is used as oscilloscope. Clicking the readout shows a popup menu with available time/div settings.

Increase/decrease oscilloscope time/div

Two buttons are available to increase or decrease the oscilloscope time/div:

Decrease the time/div one step.

Increase the time/div one step.

The steps that are taken are the time/div settings that are available in the time/div menu.

Increase/decrease oscilloscope time resolution

Two buttons are available to increase or decrease the oscilloscope time resolution:

Decrease the time resolution one step. Increase the time/div one step.

An oscilloscope measurement has a record length and a sample frequency. This gives a total measuring time. With each subsequent click on one of these buttons, the record length and sample frequency are respectively halved or doubled. The total measuring time remains equal, but the time resolution will decrease or increase.

Trigger now!

Force the instrument to trigger now (hotkey space bar).

Predefined trigger time out settings

Three buttons are available to set the trigger time out:

Set the trigger time out to zero (hotkey 0) Set the trigger time out to 1 second (hotkey 1) Set the trigger time out to infinite (hotkey w)

OSCILLOSCOPE GRAPH The oscilloscope can have one or more graphs, each displaying one or more signals, where each graph can display different parts of a signal. Graphs can display the signal(s) in Yt mode or in XY mode, with or without interpolation. Colors of all items in a graph can be set to any required value. Graph dimensions can be adjusted to any required size, graphs can be located in one single window or in separate windows, which can be located anywhere on the desktop. Cursors are available to make on screen measurements, as well as a t=0 line to indicate the trigger moment. Signals can be given descriptive names and a legend is available to simplify identifying the displayed signals. Text labels can be placed to mark interesting parts of the signal(s). To reveal all details of the measured signals, unlimited zooming is available in both vertical and horizontal direction. All zoom actions can be undone with an undo zoom function. OSCILLOSCOPE CONTROL Controlling the oscilloscope is done through customizable toolbars, through popup menus and by hotkeys. A quick function toolbar is available for often used functions.

STORAGE OSCILLOSCOPE Storage oscilloscope An instrument that is used to measure fast nonrepetitive signals. It does this by capturing the signal on demand and continuing to display it until reset. This can be achieved in two ways: a digital storage oscilloscope samples the incoming signal, stores these samples, and displays them; other storage oscilloscopes use a special storage cathode-ray tube that retains the image by mapping it as a charge pattern on an electrode behind the screen; the pattern then modulates the electron beam to give a picture of the captured signal.

Trace storage is an extra feature available on some analog oscilloscopes; they used direct-view storage CRTs. Storage allows the trace pattern that normally decays in a fraction of a second to remain on the screen for several minutes or longer. An electrical circuit can then be deliberately activated to store and erase the trace on the screen. The storage is accomplished using the principle of secondary emission. When the ordinary writing electron beam passes a point on the phosphor surface, not only does it momentarily cause the phosphor to illuminate, but the kinetic energy of the electron beam knocks other electrons loose from the phosphor surface. This can leave a net positive charge. Storage oscilloscopes then provide one or more secondary electron guns (called the "flood guns") that provide a steady flood of low-energy electrons traveling towards the phosphor screen. Flood guns cover the entire screen, ideally uniformly. The electrons from the flood guns are more strongly drawn to the areas of the phosphor screen where the writing gun has left a net positive charge; in this way, the electrons from the flood guns re-illuminate the phosphor in these positively-charged areas of the phosphor screen. If the energy of the flood gun electrons is properly balanced, each impinging flood gun electron knocks out one secondary electron from the phosphor screen, thus preserving the net positive charge in the illuminated areas of the phosphor screen. In this way, the image originally written by the writing gun can be maintained for a long time many seconds to a few minutes. Eventually, small imbalances in the secondary emission ratio cause the entire screen to "fade positive" (light up) or cause the originally-written trace to "fade negative" (extinguish). It is these imbalances that limit the ultimate storage time possible. Storage oscilloscopes (and large-screen storage CRT displays) of this type, with storage at the phosphor, were made by Tektronix. Other companies, notably Hughes, earlier made storage oscilloscopes with a more-elaborate and costly internal storage structure. Some oscilloscopes used a strictly binary (on/off) form of storage known as "bistable storage". Others permitted a constant series of short, incomplete erasure cycles which created the impression of a phosphor with "variable persistence". Certain oscilloscopes also allowed the partial or complete shutdown of the flood guns, allowing the preservation (albeit invisibly) of the latent stored image for later viewing. (Fading positive or fading negative only occurs when the flood guns are "on"; with the flood guns off, only leakage of the charges on the phosphor screen degrades the stored image.

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