Hello, welcome to Analog Arts arbitrary function generator tutorial.
Please feel free to download the Demo application software from analogarts.com to help you
follow this tutorial.
For this presentation, we use a 150 MHz generator, one of the instruments of SL987.
This instrument offers a set of standard signals as well as the ability to edit and generate
waveforms.
The application window consists of an editor panel, a navigator panel, a standard signal panel, an
output panel, and a utility panel.
Each individual button in these panels allows the user to perform a unique task. Together, they
control the various features of the generator.
In order to illustrate these features, we connect the output of the generator to the SL987's
oscilloscope CH1 input using a coax cable.
We also connect the external trigger input of the oscilloscope to the "SYNC" output of the
generator for triggering.
The buttons marked with "Standard" and "Arbitrary" in the output panel, indicates which mode
of operation is being used. It also shows the output signal of the generator.
To generate a signal in the standard mode of operation, simply switch on its name in the standard
signal panel.
For convenience, the corresponding parameters of a function are listed only when it is selected.
For example, choosing the square-wave from the list makes the duty cycle panel appear. And for
a DC signal, only one parameter, the "DC Level" is listed.
To change the unit of a parameter, simply click on it.
The parameters of a signal can be changed either by entering the desired value or by the scrolling
of the mouse wheel.
Switching on a signal with more than one type, directs the user to the list of its varieties.
Selection of a "Ramp" signal, for example, shows its different variations: "Triangle", "Falling
Ramp", and "Rising Ramp".
The button marked "Back" brings back the previous signal list.
Switching on the "Modulated" button, guides the user to the "Modulation" list. It offers, AM,
FM, sweep, burst, and digital types of modulation.
The "AM" button opens a window by which the modulating signal can be described.
The modulating signal and its parameters can be specified from this menu.
If you have already created a custom wave and wish to use it as the modulating signal, select the
"Edited Waveforms".
The "Reset" button resets the window to its default settings. And the "Exit" button closes the
window.
To open the window, click on the selected modulation signal.
The carrier frequency, the amplitude and the offset of the output are listed in the standard signal
panel.
Generating FM signals is very similar to generating AM signals.
For FM signals, switch on the "FM" button and enter your desired output parameters.
Sweep signals are also simple to generate. Its corresponding parameters can be specified as in
other signals. To make the sweep linear, click on the "Linear" and for exponential sweep, turn on
the "Exponential" button. The direction of the sweep is determined by the button at the right side
of the "Exponential" button. When it is labeled "Up", the direction is from low to high. And
when it is labeled "Dn" the direction is from high to low. The output panel shows the symbol of
the generated signal.
Clicking on the "Burst" button opens a window called "Burst Carrier Signal". It enables the user
to select a burst signal and specify its parameters. The number of cycles in the output is a
function of burst rate and the frequency of the burst signal. If a burst count number exceeds the
allowable limit, The "Burst Count" text box would highlight this condition in red. Pressing the
"Enter" key in this situation notifies the user about the burst count allowable range.
In the default mode, when the "Sample" button is on, burst signals are generated continuously
according to the "Burst Rate" value. To have a gated signal, switch on the "Gated" option. In this
mode, connect the gating signal to the "SYNC" signal of the generator. To output an individual
burst of a signal, first choose the "Single" mode, and then click on the "Send Burst" button to
send it.
Switching on "Digital" features the "ASK", "FSK", and "PSK" types of shift keying modulation.
Respectively, they represent digital data as variations in the amplitude, the frequency, or the
phase of a carrier wave. Therefore, we have to specify the modulating signal and its parameters
both for the "Space '0' " and for "Mark '1' " to represent zeros and ones. Be sure, the proper
button is on when specifying the modulating signal parameters and also when the signal is
applied.
To have a gated signal, turn on the "Gated" button and also connect the "SYNC" BNC of the
generator to the gating signal.
The "Special" signal category offers "Pulse", "Sinc", "Rising Exponent", "Falling Exponent", and
"Cardiac" signals. To generate each signal, switch it on and specify your desired parameters.
For arbitrary signals, first we have to edit the signals.
The editor panel offers 4 different types of signal editing. They are manual, pen, line, and insert.
Each mode is activated by its corresponding button.
In the manual mode, the user can edit the signal point by point. To do this, simply enter the
memory location and the output voltage. Then, to apply the values, press the enter key. This is a
suitable method to generate precise signals.
To output the edited signal, turn on the "Arbitrary" button in the output panel and then click on
"Apply The Edited Wave" button.
For convenience, the horizontal and the vertical coordinates of the mouse are always displayed
near its position.
Pen editing, as its name would suggest, makes the mouse work like a pen while its left button is
held down. This is a convenient way to create waves.
In the line editing mode, each left click of the mouse marks the beginning of a new line. Notice
that in this mode, the edited section is in yellow color. The right click of the mouse ends the
editing.
Clicking the "Insert" button on opens the "Insert Signal Editor", which allows the user to
describe the insert signal and also state the insert position.
In the parameter list, the "Insert Point" is the memory location in which the first point of the
signal would be placed. And the "Insert Span" is the amount of allocated memory for the signal.
The "Cycles" parameter is the number of signal cycles in the allocated memory.
Once memory specifications are entered, select the type of the signal to be inserted, and specify
its parameters.
Then, to apply the edited memory, click on the "Apply" button.
There are also copy, cut, and paste actions. To select a segment of the signal for cutting or
copying, drag the mouse on the intended segment. Then, to copy or to cut the segment, right
click the mouse to open the copy menu and choose the desired action from the menu. A cut or a
copied section can be inserted into the signal by the "Paste" option. A left click on the option
pastes the segment at the location of the mouse. This location is specified in the "Paste Initial
Point" text box, which appears on the screen as soon as the mouse is over the "Paste" option.
This text box enables the user to modify the insert position.
Clicking on the "Clear" button clears the editor screen. This results in a 0V signal.
The "Undo" and the "Redo" buttons do exactly what their name would suggest; they bring the
editor to the previous and the next 100 states.
The "Zoom In" button places a rectangular zoom area on the screen. This zoom area, which is
highlighted in pink, can be modified as needed. Each side of the rectangle can be dragged in
both directions by the mouse. Also, this area can be moved. To move it, left click inside the area,
hold the left button down, and then move it to the intended position. Once the zoom area is
defined, click on the "Zoom In" to expand it.
The "Zoom Out" button makes the screen show a bigger portion of the signal, almost twice
bigger.
The vertical and horizontal zoom buttons, marked by two parallel vertical and horizontal bars,
offer vertical and horizontal zooming.
Clicking these two buttons places a corresponding pink area on the screen, which can be dragged
by the mouse and expanded by pressing the "Zoom In" button.
To have the full view of the signal, click on the "Home" button.
To center the screen with respect to a memory location, simply enter the memory location in the
center lime colored text box in the bottom of the editor screen.
The "Scroll" button in the on condition enables dragging the screen by the mouse.
The navigator panel also offers another method to scroll the editing window. To do this, grab the
orange box in the panel and drag it by the mouse.
This generator features "Windowing", "Filtering", and "Math" signal processing.
For "Windowing", click on the "DSP" button first and in the DSP menu select "Windowing".
Then, choose your desired function from the windowing menu.
The "Filtering" option opens the "Filter Selection" window that allows the user to select the type
of the filter and specify its parameters.
Mathematics operations on waveforms can be performed in the "Math Operation" window. To
open this window, select the "Math" option in the DSP menu.
The text boxes, "Starting Memory Point" and "Ending Memory Point" In this window, specify
the memory segment, where the operation is performed on. Notice that the segment is
highlighted in white color in the original signal plot.
The menu labeled "Math Operation" opens a list, which features a number of mathematics
operations.
For "Add," "Subtract," and "Multiply", the "Operating Waveform" must be created first. The
"Create Waveform" button opens the "Insert Signal Editor" window, which can be used to define
the operating signal.
After the operating signal is created, to view the resulting waveform, click on the "Preview"
button.
To multiply the waveform by a factor, select the "Gain" option from the math menu. Then, enter
the gain factor in its textbox.
The "Absolute" option produces the absolute value of the signal at the output.
To limit the output, select the "Clip" option. Then, enter the high and low clip values in their
appropriate text boxes.
To invert the signal, select the "Invert" option.
When the "Mirror" option is selected, the resulting waveform would be a mirrored version of the
signal.
The signal can be resized, both vertically and horizontally. When the "Resize" option is selected,
the "X Span" and the "Y Span" text boxes allow the user to set the resizing area. Resizing maps
the signal defined by the memory points into this area. Notice that the resulting waveform is
centered around the middle of the memory.
The "Expand to Fit" operation expands the signal to fit into the entire memory.
The "Apply" button applies the operation to the edited signal each time it is clicked.
To close the "Math Operation" window, click on the "Exit" button.
In the editor panel, clicking on the "Hardware" button opens a menu, which allows the user to set
the sampling rate, the memory size, and to enable or disable the reconstruction filter.
To change the sampling rate, select the "Sampling Rate" and then enter the new sampling rate in
the corresponding text box. The new sampling rate is applied when the enter key is pressed.
The memory size can be changed in a similar manner. For this, select the memory option, enter
the size, and then press the enter key.
Clicking the "Filter Disabled" option disables the filter while the "Filter Enabled" enables it. A
checkmark symbol shows the selected option.
The edited waves can be saved at anytime. The "Save Wave" and the "Recall Wave" buttons
facilitate the process.
The utility panel on the top of the screen assists the user to perform a number of tasks. The
"Reset" button brings the generator to its default condition.
The arbitrary generator settings can be saved in a text file. To do this, simply click on the "SaveSettings" button.
The "Recall Settings" button allows the user to load any desired settings.
In addition to the settings, the user can save the generator plot and recall it at anytime. The plot
can be saved in a variety of formats.
The "Calibrate" button starts the self calibration process of the generator. This process usually
takes about 10 seconds to complete.
Clicking the "Print" button sends the generator plot to a printer selected by the user.
The "Help" button guides the user to an online Analog Arts information site that hosts a
collection of user manuals, specifications, and useful application documentations and videos.
We hope you have enjoyed this presentation.
For additional information please send an email to info@AnalogArts.com.
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