AM/FM Receiver Tutorial: Definition, Block Diagrams

Do you want to learn about AM and FM? Block diagrams for both AM and FM could help you understand their working concepts.

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AM and FM are the two types of wave transmission tools to convert a wave or sound signal to another device like a TV, speaker, or mobile phone.

AM was used firstly for phone calls where a sound wave was converted into an electronic signal, making it more appropriate at the receiving end. Just like AM, FM was used for the same purposes, but this time, the sound is noise-free and has better results.

Both AM and FM have their significance and drawbacks. However, FM is considered more valuable and greatly impacts our lives.

In this guide, you are going to learn more about these two with the help of block diagrams. These block diagrams will make it easier to learn more about AM and FM.

In this article
  1. FM Receiver vs. AM Receiver
  2. How to Make Such Block Diagrams?
  3. Conclusion

FM Receiver vs. AM Receiver

Amplitude Modulation AM and Frequency Modulation FM are the radio signals used in broadcasting. Electromagnetic waves are used to transmit signals from one end to the other.

Comparison between AM Receiver and FM Receiver

AM Receiver FM Receiver
In AM, the radio signal is transmitted by varying the amplitude of the signal, keeping the frequency constant. On the other hand, FM works on the principle of varying the frequency of the carrier, and the amplitude is kept constant.
AM method was first used in 1870. The FM audio transmission was used in the 1930s by Edwin Armstrong.
When it comes to sound quality, AM has a poorer reputation than FM. However, it is cheaper to use as the bandwidth is lower and can be transmitted to longer distances. In one frequency range, there could be more stations. FM has a higher bandwidth, making it more reliable, and the sound quality is better than AM. It is only impacted by the physical barriers.
The frequency range for the AM is approximately 1200 bits per second. It ranges from 535 Hz to 1700 Hz. The frequency range for the FM is a bit higher, ranging from 1200 to 2400 bits per second.
AM is simpler, but synchronization is needed to maintain the signal as it is received from the transmitter. FM is complex as the modulating signal needs to be converter after transmission. Voltage to frequency and frequency to voltage while sending or receiving the signals, respectively.
AM is more affected by voice as the amplitude varies in these types of signals. In FM transmission, noise is not an issue as the amplitude of the transmitted signals doesn't change.

FM Receiver Block Diagram

FM radio has been a great source to pass information from one place to the other. Most of the stations choose FM radios over AM due to the improved sound quality.

The characteristics of the FM radio make it more complex, where it works on pre-emphasis and de-emphasis. These are the processes in which a certain frequency is boosted or reduced, respectively.

Here is a block diagram for the FM receiver that tells us more about the operations running in the system. This diagram will help you learn the basics of the FM Receiver.

how to draw a block diagram for an FM receiver
  • It starts with an antenna that receives the signals and intercepts them. The signal then passes through the Rf Amplifier (Radio Frequency Amplifier). The signals the antenna receives are weak and need amplification. The RF amplifier amplifies these signals and helps reduce the noise effects.
  • Mixer is the next stage, where two signals are received, one from the Rf amplifier and the other one from the oscillator. In combination with these two signals, a single signal is generated called the IF signal.
  • Suppose the signal is processed through the IF Amplifier, which amplifies the IF signals and sends them to the FM Demodulator. The Demodulation changes the signals through de-emphasis and generates an output signal.
  • This output signal is received by the Audio Frequency voltage amplifier. This AF voltage amplifier converts the signals into the original voice generator through the transmitter.
  • AF power amplifier enhances that signal passed through the AF voltage amplifier. The output coming out of the power amplifier is directly applied to the speaker.

AM Receiver Block Diagram

The block diagram for the AM receiver helps us understand the logistics of the system. The block diagram for the AM is similar to the FM. However, we'll see how they are helpful in modifying the audio.

Here is the basic description of all the parts of the AM system.

how to draw block diagram for AM receiver
  • The first part of the AM system is the antenna. This antenna doesn't transmit information. It is only used to receive the signals. The carrier wave is received by the antenna and converted into the current pulse.
  • After passing the wave through an antenna, it becomes a current and is further sent to the Amplifier. This Amplifier is used to amplify the signal to make it ready for further operations.Sometimes, an oscillator is also used to produce a signal for better operation.
  • Next comes the IF stage, which is where the applied signal is further processed to make it ready for the demodulator.
  • Demodulators find the signal and extract it through a specific circuit. It sends the modified signal to the Amplifier.
  • Another amplifier is used to enhance the credibility of the weak signal that has just passed through the IF stage. This Amplifier makes the signal ready for the speaker.
  • Lastly, the electronic signal is converted into voice, making it loud and precise. However, with technology, AM was further used in TV and other devices as well.
  • The Block diagram is used to understand a complex system visually. It describes all the working processes in a system.

How to Make Such Block Diagrams?

Method 1: Starting from scratch

1.First of all, all you need to do is to find the components of the diagram. Having knowledge of these components and their working is essential. Download a diagram maker and Draw some blocks in your diagram and give them a direction of flow.

draw blocks to start the diagram

2.Label each block of the system. Labeling makes it way easier to understand any model. It is better to label inside the block to make it visually appealing.

3.Draw the relationship lines among the blocks. Use the arrowhead line to make it more directional.

draw blocks to start the diagram

4.Add colors to the blocks to make them more aesthetic.

add-colors-in-the-diagram

You need to be an expert in creating all those components and arranging them in the right way. However, if you are not a graphic designer or expert in this field, we have sorted things for you as well. Check out Method 2 and get things done quickly.

Method 2: Starting with a template

A template is a way forward for you if you don't want to take time to draw the blocks and components. Choosing the right kind of template could be itchy, but it still saves time. You can add or remove any component needed. A readymade template saves a lot of time, and you just need to move the components on the canvas to get things done quickly.

Here is an example for you to draw a block diagram from a template.

1.Click the template below to download it and open the file.

choose a template

2.Remove unnecessary elements in the diagram.

remove elements that are not needed from the template

3.Arrange the remaining components in order with their relationships and label them according to your needs.

label the blocks and add colors

That's it. Your block diagram is ready. If you need some kind of complex diagram, there are other templates to choose from as well. Check out the template community and see which template matches your needs.

Conclusion

In this guide, we have learned about the basic composition of the AM and FM modulation and their working with the help of block diagrams. These diagrams make your work visually appealing and help anyone understand the logistics.

However, sometimes, it is difficult for a newbie to start drawing these diagrams. So, a readymade template could help us in such scenarios. You can choose templates from EdrawMax for you to start with. A template could have all the components or elements that are required to complete your block diagram. So, it is worth using as it saves a lot of time for you.

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Edraw Team
Edraw Team Apr 15, 24
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