How a Car Radio Works
#17
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I took apart a Toyota radio to see what's inside and how it works. I made a short video on the simplified way it works, of course new radios are more complex:
https://www.youtube.com/watch?v=piX-_g7-mXo
The radio I took apart was a single DIN, AM/FM/CD radio:
![](https://i.imgur.com/Ci2WETJ.jpg)
Radio lid removed:
![](https://i.imgur.com/ly4rAgP.jpg)
The main motherboard has a number of main components that make up the radio, including the antenna input, the demodulator, tuner, equalizer, micro-controller, amplifier, communication bus controller, human interface input/output, power distribution and CD ROM input:
![](https://i.imgur.com/IhGnsFo.jpg)
Here's an overall system diagram of how things are laid out and work inside the radio:
![](https://i.imgur.com/0CYvdRF.jpg)
Here's a closer look at the radio tuner (digital) and the demodulator:
![](https://i.imgur.com/FgP9DvN.jpg)
If you remember physics class, AM stands for amplitude modulation, and FM stands for frequency modulation. Basically the amplitude or frequency of the radio waves are varied in order to carry a signal, which the demodulator turns into a voltage audio signal:
![](https://i.imgur.com/5uhXzL9.jpg)
This is the back of the human interface board, including the LCD driver and buttons:
![](https://i.imgur.com/FZfXbEf.jpg)
Moving on to the CD drive, there's 3 motors, one to turn the CD, one to load the tray, and one to move the laser head along the radius of the disk:
![](https://i.imgur.com/apGZEUi.jpg)
Closer look at the laser head:
![](https://i.imgur.com/AJCAcP6.jpg)
Here's an overview of how it works, essentially light is reflected back based on the information burned onto the disk. A photo sensor pics up this light and turns that into usable information:
![](https://i.imgur.com/vsoN20G.jpg)
![](https://i.imgur.com/KhIRrAd.jpg)
The last piece to a stereo is its output in the form of sound. This is done by repeatedly moving a paper cone back and forth at high frequency. This creates pressure waves in the air which we hear as sound.
The paper cone is controlled by an electromagnet:
![](https://i.imgur.com/7aCxCNv.jpg)
And that's pretty much the very basics of how a car stereo works!
![](https://i.imgur.com/RQNcC4M.jpg)
- Enjoy
https://www.youtube.com/watch?v=piX-_g7-mXo
The radio I took apart was a single DIN, AM/FM/CD radio:
![](https://i.imgur.com/Ci2WETJ.jpg)
Radio lid removed:
![](https://i.imgur.com/ly4rAgP.jpg)
The main motherboard has a number of main components that make up the radio, including the antenna input, the demodulator, tuner, equalizer, micro-controller, amplifier, communication bus controller, human interface input/output, power distribution and CD ROM input:
![](https://i.imgur.com/IhGnsFo.jpg)
Here's an overall system diagram of how things are laid out and work inside the radio:
![](https://i.imgur.com/0CYvdRF.jpg)
Here's a closer look at the radio tuner (digital) and the demodulator:
![](https://i.imgur.com/FgP9DvN.jpg)
If you remember physics class, AM stands for amplitude modulation, and FM stands for frequency modulation. Basically the amplitude or frequency of the radio waves are varied in order to carry a signal, which the demodulator turns into a voltage audio signal:
![](https://i.imgur.com/5uhXzL9.jpg)
This is the back of the human interface board, including the LCD driver and buttons:
![](https://i.imgur.com/FZfXbEf.jpg)
Moving on to the CD drive, there's 3 motors, one to turn the CD, one to load the tray, and one to move the laser head along the radius of the disk:
![](https://i.imgur.com/apGZEUi.jpg)
Closer look at the laser head:
![](https://i.imgur.com/AJCAcP6.jpg)
Here's an overview of how it works, essentially light is reflected back based on the information burned onto the disk. A photo sensor pics up this light and turns that into usable information:
![](https://i.imgur.com/vsoN20G.jpg)
![](https://i.imgur.com/KhIRrAd.jpg)
The last piece to a stereo is its output in the form of sound. This is done by repeatedly moving a paper cone back and forth at high frequency. This creates pressure waves in the air which we hear as sound.
The paper cone is controlled by an electromagnet:
![](https://i.imgur.com/7aCxCNv.jpg)
And that's pretty much the very basics of how a car stereo works!
![](https://i.imgur.com/RQNcC4M.jpg)
- Enjoy
Have a great weekend!
BestJeff aka harleygirl
’03 SC and ‘09 RX Pebble Beach
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