LabVIEW DSP allows the user to implement
standard IIR digital filters designed using a filter designsupplemental program, called Digital Filter Design Toolkit. The DFD
toolkit is an add-on module to LabVIEW (not LabVIEW Embedded). Thismodule allows the user to design complex filters, save them and
implement them using LabVIEW DSP.
New Block Diagram with DFD Filter
Go to the Functions palette and add the DFD
Filter Express VI to your existing Block Diagram: Functions»SignalProcessing»Filters»DFD Filter
Wire the Express VI as shown in Figure 6.
The output of the Add function is the input “Signal” of the ExpressVI and the “Filtered Signal” goes into the Analog Output. Set the
function generator’s signal to a frequency of 500 Hz.
Follow the steps below to implement alowpass filter that will be implemented on the DSP. Launch LabVIEW
by going to Start»All Programs»National Instruments»LabVIEW7.1»LabVIEW. Let’s try to understand what is happening. We first
launched LabVIEW Embedded Edition which allowed us to target theDSP hardware and run our program. Now, we are launching LabVIEW,
not LabVIEW Embedded Edition. The program you built earlier shouldstill be open. We will use the Digital Filter Design Toolkit
available in the LabVIEW environment to design the filter.
Create a blank VI (New»Blank VI).
Switch to the Block Diagram and drop a DFD Classical Filter
Design on the Block Diagram: It is in Functions»AllFunctions»Digital Filter Design»Filter Design»DFD Classical Filter
Design.
In the DFD Classical Filter Design Express VI, enter the
following settings:
Filter Type: Lowpass
Sampling Frequency: 16000 Hz
Passband Edge Frequency: 1000 Hz
Passband ripple: 3 dB (standard for Butterworth
filters)
Stopband Edge Frequency: 1500 Hz
Minimum stopband attenuation 20 dB
Design Method: Butterworth
Leave the other settings to their default values.
DFD Classical Filter Design Configuration Window
Check the graph to the left to make sure the
filter response appears as expected and click “OK” to set theconfigurations.
Some filter parameters are described
below:
Sampling Frequency – self-explanatory. Make sure to set it to
the sampling frequency that you plan on using!
Center Frequency – (not used for lowpass filters). Set this
to the middle frequency of the passband for Bandpass/Highpassfilters or the middle frequency of the stopband for Bandstop
filters.
Bandwidth – Set this to the frequency width of the passband
(stopband for Bandstop filters). Recall that Lowpass filters have alower passband frequency of 0 Hz and that Highpass filters has an
upper passband frequency of Fs/2.
Stopband Attenuation – Set this to the desired attenuation in
dB at the edge of the stopband. For Bandstop filters, thisparameter must be negative (because the stopband is really the
passband). For all other filter types, this parameter must bepositive.
Passband Ripple – Set this to the desired attenuation (in dB)
at the edge of the Passband. For Butterworth filters, the standard(but not required) value to use is 3 dB.
Filter Order N – Set this to the desired filter order.
However, after you press the Apply button, the program calculateswhich filter order you need to meet the given specs. For most
applications, then, you can put any number here and then change itto the necessary value when instructed. There may be some
situations, however, when you want to force the filter order to besome set value. In this case, the desired specifications may not be
met.
Regarding calculation of filter order N: This program uses the same design equations that we use in EE 453. For IIR filters, the program automatically does prewarping.
Build the following Block Diagram to save
the filter settings: Drop a “DFD Save to File” VI on the BlockDiagram. This VI is located at Functions»All Functions»Digital
Filter Design»Utilities»DFD Save to File. Wire the Block Diagram asshown in Figure 6.
Filter Design
Run the filter design VI you just built.
When prompted to save your design, navigate to your folder and saveyour filter under any chosen name. Save and close this VI.
Questions & Answers
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
