Inversely Related
When one goes up, the other goes down.
When one goes down, the other goes up.
They always move in opposite directions.
Think of a seesaw. When your side goes down, the other side goes up. They can never move in the same direction.
Drag either circle up or down
No matter how hard you push, both sides can never go up at the same time. That is what inversely related means.
Drag the seesaw and watch what happens on the graph.
When two things are inversely related, the graph slopes down from left to right. As one value climbs, the other drops.
In ultrasound, some of the most important measurements are inversely related to each other. Here are two you will see again and again:
These terms will come up in detail later. For now, just notice: they follow the same seesaw pattern.
Definition: How many times a sound wave repeats each second.
Example: Think of a heartbeat. A faster heartbeat means a higher frequency. A slower heartbeat means a lower frequency.
Definition: How long it takes for one complete cycle.
Example: When frequency goes up, each cycle has less time to complete, so period goes down. They are inversely related.
Quick Check
If one value increases and the other decreases, they are:
Period and frequency are inversely related. If period increases, what happens to frequency?
On a graph, an inverse relationship slopes: