28119 Parallax Inc, 28119 Datasheet - Page 55

• Manufacturer Part Number: 28119
• Description: KIT UNDERSTANDING SIGNALS
• Manufacturer: Parallax Inc

Specifications of 28119

• Lead Free Status: Contains lead
• Accessory Type: Oscilloscope
• Interface Type: USB
• For Use With/related Products: BASIC Stamp® 2 and Board of Education
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

The nature of sound is complex: only pure tones are made with one frequency, but most
applications use tones made of mixed frequencies. Proper use of the OPTAscope can
help you identify the component frequencies within a complex sine wave. You may use
the Vertical Bars cursors to measure the pattern in a simple mixed signal, and use the FFT
function to identify component frequencies.
frequency, adjustment of the trigger level may be required to keep them “in focus”. The
Cursor Settings switch’s Paired Bars setting option allows you to measure both frequency
and amplitude.
Exercises
1. Write a program to generate a signal like the one shown in Figure 3-12 below.
2. Use the FFT function to confirm the components of your signal.
The primary frequency is 800 Hz and the secondary is 8 kHz. You may need to
adjust your Horizontal and Vertical dials to get a similar signal. Give it a try!
Since wave amplitudes can vary with
Figure 3-12:
An 8 kHz sine
wave
superimposed
upon an 800 Hz
sine wave