28128 Parallax Inc, 28128 Datasheet - Page 104

• Manufacturer Part Number: 28128
• Description: KIT BASIC ANALOG/DIGI PARTS ONLY
• Manufacturer: Parallax Inc

Specifications of 28128

• Accessory Type: ADC, DAC
• Product: Microcontroller Accessories
• For Use With/related Products: BASIC Stamp® 2 and Board of Education
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Page 94 · Basic Analog and Digital
Voltage
Period
Amplitude
DC Offset
Time
Figure 5-4: Horizontal Output Sample of Time-Varying Waveform
A more conventional way of viewing time-varying waveforms is shown in Figure 5-4.
This is the way they are typically displayed using an oscilloscope. The amplitude, period
and DC offset are three common measurements taken using an oscilloscope. Note how
the time axis is the horizontal axis in this picture, and the voltage axis is the vertical axis
The period of a waveform is the amount of time it takes to repeat itself. In this case, that
amount of time is about 1 second. The frequency is the inverse of the period, so we can
use a simple equation to determine the frequency when we know the period:
f = 1/T
The term f is the frequency, measured in Hertz (Hz), and T is the period, measured in
seconds (s). Since the period is one second, and 1 ¸ 1 = 1, the frequency is also 1 Hz. As
another example, if the period is 1/100 of a second, the frequency is 1, 1/100 = 100 Hz.
Amplitude and DC offset are two quantities related to voltage that are measured
differently for different signals. The amplitude shown in Figure 5-4 is called the peak-to-