70009 Parallax Inc, 70009 Datasheet - Page 55

• Manufacturer Part Number: 70009
• Description: BOOK UNDERSTANDING SIGNALS
• Manufacturer: Parallax Inc
• Type: Signal Analysisr

Specifications of 70009

• Style: Book
• Title: Understanding Signals
• Contents: Guide to Generate, View and Measure Wave Forms
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 70009PAR

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