How was the first radar made into a screen that produced a dot?

Question

I understand they managed to emit a sound wave that came back, but how in the world did they digitize that?

In: 4

Answer 1

Radar is not sound it is radiowaves, sonar is sound.

The displays were [https://en.wikipedia.org/wiki/Cathode-ray_tube](https://en.wikipedia.org/wiki/Cathode-ray_tube) the same technology that was used in TV until the last 20 years.

It is a tube with a vacuum in it where electrons are accelerated to the front of the screen where there is a phosphorescent screen that glows where the electron beam hits it. The phosphorescent was just a single color usually green because phosphor was used. TV used a material that emitted white light for black and white TV and red, green, and blue for color TV.

The electron beam is controlled by a magnetic field or electrostatic deflection. In both cases, you can use electrical signals to control the deflection. The brightness of a pixel depends on the input current to the election cannon.

Radar and sonar work by you sending out a pulse of radio waves or sound and then listening to what is reflected back. Because both sound and light travel at finite speed the distance to an object depends on the time it takes for the reflection to return to you

So for a radar or sonar, you create a single that moves the electron beam out at a constant rate when a signal is sent. The direction it moves it depends on the direction of the radar dish. The signal you receive back then controls the intensity of the election cannon, after some amplification stage.

The earlier system did not use a circle. You have contact brightness and you let time be the X-axis. You control the Y.axis with the return signal strength. This is how an oscilloscope works, one in one direction and signal strength in the other. The first rada display was simply oscilloscopes. When radar was invented they were established technology, the first with a CRT display was made in 1897, the first radars are from the 1930s

Broadcast TV with CRT display was introduced in the 1930s.

Sonar existed in WWI with prototypes. I am not sure if displays or just earphones were used. There was usage with displays in WWII