ATEVK1104S Atmel, ATEVK1104S Datasheet - Page 8

• Manufacturer Part Number: ATEVK1104S
• Description: KIT EVAL FOR AT32UC
• Manufacturer: Atmel
• Series: AVR®32 UC3r
• Type: MCUr

Specifications of ATEVK1104S

• Contents: Board, Cables
• Tool Type: Development Kit
• Cpu Core: AVR 32
• Data Bus Width: 32 bit
• Processor Series: AT32
• Processor To Be Evaluated: AT32UC3A3256S
• Interface Type: USB, JTAG, SD Card, Nexus, MMC
• Core Architecture: AVR
• Operating Supply Voltage: 5.5 V
• For Use With/related Products: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.7 Analyzing filters in the frequency domain
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AVR32908
Analyzing a signal by FFT:
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Changing amplitude:
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When the amplitude of signal 2 increases above 0.50, some new components may
start to appear. This is caused by signal saturation, an effect we will cover in more
detail in the next hands-on training.
The FFT function is self scaling. When the amplitude of signal 2 is higher than that of
signal 1, the FFT output is scaled. It may appear as if signal 1 decreases in amplitude
as signal 2 starts to define the maximum of the display.
Viewing the frequency domain:
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Turning on low-pass filtering:
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High-pass filtering:
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Changing frequency:
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Push and hold the BACK button for 3 seconds to reset the signals and filters.
Select the output signal and push FUNC 1 to enable FFT view.
Select signal source 2.
Change the frequency to 4 kHz.
Observe how the signal component seen in the FFT view shifts to the right with
increasing frequency.
Reduce the frequency, and see how the signal component moves to the left.
Zoom in on the output signal to see more details.
Select signal source 2.
Change the amplitude to 0 and observe how the signal component disappears.
Change the amplitude to 0.9999 and observe how the signal component grows
Push and hold the BACK button for 3 seconds to reset the signals and filters.
Select the FFT view for both the combined signal and the output signal
Select the filter.
Enable the low-pass filter.
Observe how the filter allows the 433 Hz of signal 1 to pass though, while the 2
kHz of signal 2 is dampened.
Select the filter and enable the high-pass filter.
Observe how this gives the opposite effect of the low-pass filter.
Set the amplitude of both signal sources to a value in the 0.40 – 0.45 range.
In the FFT view of the combined signal, the two components will have equal
power, but in the filter output only the high frequency component is visible.
Increase the frequency of signal 1.
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