020 What is an SDR - python-can-define-radio/sdr-course Wiki

What is an SDR?

Well, it's a Software Defined Radio. But you're probably looking for a more in-depth answer than that.

So, let's look at what a radio is. Even before that, we'll start with what a wave is.

What is a wave?

Slinkies and Sound

Here's a slinky.

What's waving? The metal.

You can also make the metal wave longitudinally.

But what if you wanted to convey audio?

Let's talk about the classic string-between-two-cans.

-------                     -------
  Can  ------- String ------  Can  
-------                     -------
  1. What's happening?
  2. What's waving?
  3. Is it a longitudinal wave or a transverse wave?

(discuss in small groups. For more info, see this video.)

Microphones

Let's imagine a new, similar setup:

--------------                   ----------
  Microphone -------- Wire ------  Speaker
--------------                   ----------

What's the difference between this and the string+cans setup?

What kind of signal is carried on the string? On the wire?

(discuss in small groups.)