Pulse Amplitude Modulation (PAM)
This week's laboratory investigates Pulse Amplitude Modulation (PAM). We will be
using the 4066 chip to sample small pulses of a sine wave. The 4066 is an analog
switch IC which will output whatever is on the input when the control is high.
Since it is a CMOS chip the voltage levels are very important. We will use
short pulses from a 2206 as our control and the frequency generator as the input.
Determine the following, and record in your lab notebook:
- Pulse Generation (XR-2206)
- sketch the circuit which will give you a pulse wave output
- determine what timing resistors to use to achieve a duty cycle of 20ms
- using the resistor values chosen above, determine what timing capacitors are
required to achieve a frequency of 4Hz, 10Hz and 20Hz
- Pulse Amplitude Modulation
- determine your supply voltages (remember we only have -12V, 0V, +5V, +12V)
- determine the maximum and minimum voltage for the input signal to the 4066
- determine the voltage levels for the control signal to the 4066
- choose what pins you will use to connect your input signal, control signal and the output
- Signal Generator
- determine the amplitude (voltage levels) for the input signal based on the minimum
and maximum voltage you found above for the input signal
- Write out a parts list
Datasheet: XR2206
[Copyright 1972 EXAR Corporation. Datasheet June 1997]
Datasheet: MC14066B (4066)
[Copyright Semiconductor Components Industries, LLC, 2000]
Table 1: Available Parts
| Resistors (Ω) |
Capacitors (μF) |
| 10 |
1k |
0.001 |
0.01 |
| 3.9k |
4.7k |
0.033 |
0.047 |
| 5.1k |
10k |
0.1 |
0.22 |
| 20k |
51k |
0.33 |
0.47 |
| 100k |
1M |
1 |
10 |