Chapter 32

Classification

When an analog designer is asked how many analog cells can exist, the answer is often a large but very inaccurate number... But when the same analog designer is asked to list analog functions, he has hard time finding more than 15...

Let's make an attempt to define a list of analog functions. First of all, we may define two classes:

• The signal generators. These blocks have a supply, of course, and a signal output but no signal input. They may have control inputs.
• The signal modifiers. These blocks have a supply, of course, a signal input and a signal output. The output depends on the input. They may have control inputs

32.1 Signal generators

Among signal generators, one can think of two categories:

• DC signal generators
• Time varying signal generators

32.1.1 DC signal generators

In this category, there are mainly three members:

• Voltage generators

• Current generators

• Arbitrary resistance generators

32.1.2 Time varying signal generators

In this category, there are mainly two sub-categories

• Periodic signal generators

• Non periodic signal generators

32.2 Signal modifiers

This large class include many categories among which:

• Amplifiers
• Filters
• Modulators and demodulators
• A-D and D-A converters