Episode 8 · I/Q Signals · Series 02: RF principles

Why does a software radio keep two numbers for each sample?

A frame from the draft of episode 8, I/Q Signals

Coming soon

Release: Dec 18, 2026
Length: 3:22
Subject: Sampling

What it covers

Why a software radio keeps two numbers for each sample. A wave is an arrow that turns: I and Q fix its tip. AM, FM and SSB are three paths of that arrow. With a real voice on AM, FM and SSB, and two real stations that fold together with I alone.

Chapters

0:00Two numbers for each sample
0:14What one number cannot tell
0:35A wave is an arrow that turns
1:00How a receiver gets I and Q
1:18Above or below?
1:43Three paths of one arrow
2:09A real voice, as I and Q
2:35Two stations, one receiver
3:07A software radio

Frames from the draft

I/Q Signals: Two numbers for each sample — 01 Two numbers for each sample

I/Q Signals: What one number cannot tell — 02 What one number cannot tell

I/Q Signals: A wave is an arrow that turns — 03 A wave is an arrow that turns

I/Q Signals: How a receiver gets I and Q — 04 How a receiver gets I and Q

I/Q Signals: Above or below? — 05 Above or below?

I/Q Signals: Three paths of one arrow — 06 Three paths of one arrow

I/Q Signals: A real voice, as I and Q — 07 A real voice, as I and Q

I/Q Signals: Two stations, one receiver — 08 Two stations, one receiver

I/Q Signals: A software radio — 09 A software radio