Tag: Academia – Com System

Dear BTE-ian,

So, today is Test 2.

I am thrilled to witness your dedication and enthusiasm as you tackle Test 2 :), delving into the intricate world of Amplitude Modulation (AM).

Even in today’s an era dominated by the marvels of 5G and cutting-edge communication systems, you might be wondering why we still have the fundamentals of AM modulation in  your syllabus…

Let me share some insights that highlight the enduring relevance of AM modulation, even in today’s rapidly advancing technological landscape.

The Time-Tested Elegance of AM Modulation
Amplitude Modulation is a technique that has stood the test of time, continues to play a crucial role in the context of communication systems. While it may seem like a relic of the past, AM modulation possesses certain attributes that make it indispensable, particularly in certain applications.

1. Robustness and Simplicity
One of the key reasons for the enduring relevance of AM lies in its robustness and simplicity. Unlike more complex modulation schemes, AM is relatively straightforward to implement and offers robust performance in challenging environments. Its simplicity allows for cost-effective and energy-efficient communication solutions, making it an attractive choice for various applications, including broadcasting.

2. Efficient Use of Bandwidth
AM modulation utilizes bandwidth efficiently, a characteristic that becomes increasingly important in the era of spectrum scarcity and the proliferation of wireless devices. In scenarios where bandwidth is a precious resource, AM modulation provides an effective means of transmitting information without imposing excessive demands on the available frequency spectrum.

AM Modulation in the Heterogeneous Radio Structure
As we navigate through the intricacies of modern communication systems, the concept of a heterogeneous radio structure becomes paramount. In this context, AM modulation finds its place alongside more advanced modulation schemes within a diversified framework.

1. Complementing Digital Communication
While digital modulation techniques dominate the landscape, AM modulation complements these methods in a heterogeneous radio structure. It can coexist harmoniously with digital signals, offering versatility in addressing different communication requirements.

Recall the heterogenous radio structure in this video, shared in week 1 before:-

2. Niche Applications
AM modulation is well-suited for niche applications, such as long-range broadcasting and point-to-point communication. In the heterogeneity of today’s communication landscape, where diverse needs must be met, AM modulation provides a valuable tool in the engineer’s arsenal.

The Wider Picture: AM Modulation in the Age of 5G
As you tackle Test 2, it’s essential to understand that while 5G and advanced communication systems are at the forefront of technological innovation, the foundations laid by AM modulation still influence the broader picture. The principles you are learning in this laboratory are building blocks that contribute to your understanding of the dynamic and evolving world of communication systems.

To all my Section 1 students in BTE 3232 Communication System Design Laboratory, I extend my heartfelt wishes for success in Test 2. Embrace the challenges with the knowledge that you are acquiring skills that will serve you well in the ever-evolving field of electrical and electronics engineering.

May your understanding of AM modulation be as clear as the signals it transmits, and may you emerge from this test with newfound insights and confidence. Best of luck!

Nurul – Jan 4th, 24

 

 

 

 

 

 

 

 

 

 

 

 

 

Hello BTE-ian,

All the best in your Test 1.  Remember to submit the following in KALAM:-

1. Multisim Design File – both question 1 and 2
2. Snapshot of the simulation output.

While you’re doing this 2-hour test (assessment marks of 20%), let me recap on the Oscillator topic that we did back in Week 1, the Hartley oscillator. A reminder of how significance it is in the context  communication system design, especially in the context of a communication system design laboratory.

The Hartley oscillator, named after its inventor Ralph Hartley, is a type of LC (inductor-capacitor) oscillator that generates sinusoidal waveforms. Its distinctive feature is the use of a tapped inductor in the tank circuit, which sets it apart from other LC oscillators like the Colpitts or Clapp oscillators.

Communication systems rely on oscillators for various functions, including frequency synthesis, modulation, and demodulation. The Hartley oscillator, with its stable frequency and simplicity in design, plays a pivotal role in ensuring the accuracy and efficiency of these processes.

Within the confines of a communication system design laboratory (our class it is 🙂 ), we engaged in the practical aspects of crafting communication systems – Lab 1. The Hartley oscillator is a common choice in these labs due to its straightforward design and ease of implementation, making it an excellent tool for learning the fundamentals of oscillator design and its integration into communication systems.

When designing an oscillator, several factors must be taken into account to ensure optimal performance. In the case of the Hartley oscillator, key considerations include:

1. Frequency Stability: The oscillator must generate a stable frequency to prevent signal distortion. Careful selection of component values and precise tuning are essential.
2. Amplitude Control: Maintaining a consistent amplitude output is crucial for reliable communication. Feedback mechanisms and component sizing play a role in achieving this stability.
3. Start-Up Characteristics: Ensuring a quick and reliable start-up is vital for the oscillator to reach its stable operating point efficiently.

So, how do we describe a good oscillator?

The output of a Hartley oscillator is typically a sinusoidal waveform. This waveform can be characterized by parameters such as frequency, amplitude, and phase. In a communication system, understanding and controlling these parameters are essential for the successful transmission and reception of information.

The Hartley oscillator serves as a fundamental building block in communication systems, offering a reliable and efficient means of generating sinusoidal waveforms. Its simplicity makes it an ideal choice for educational purposes within communication system design laboratories, where students can gain hands-on experience in oscillator design and its integration into broader communication systems. As technology continues to advance, the role of oscillators like the Hartley oscillator remains pivotal in shaping the landscape of modern communication.

All the best everyone in answering your Test 1, and have a good holiday ahead. See you after the sem break.

1 – Understanding Amplitude Demodulation

In signal processing, amplitude modulation (AM) is a fundamental technique that allows us to transmit information by varying the amplitude of a carrier signal. In ths lab session – dedicated to demodulation, understanding the process of amplitude demodulation is crucial. This process, often referred to as “demodulating” or “detecting,” involves the extraction of the original message signal from a modulated carrier signal. In this blog post, we will explore the concepts and methods behind amplitude demodulation, providing valuable insights for your lab session.

The Basics of Amplitude Modulation
Before delving into amplitude demodulation, let’s briefly revisit the concept of amplitude modulation. AM is a modulation technique that superimposes a message signal onto a carrier signal by varying the carrier’s amplitude in accordance with the message signal. This modulation process enables the transmission of analog information, such as audio signals, over radio waves.

2 – The Need for Demodulation
After transmission, the receiver needs to extract the original message signal, from the modulated carrier signal. This is where demodulation comes into play. The demodulation process is essential for various applications, including radio broadcasting, radar systems, and more.

3 – Amplitude Demodulation Techniques
Amplitude demodulation is the process of retrieving the original message signal from an AM-modulated carrier signal. There are several methods to accomplish this task, and we’ll explore two common techniques:

4 – Envelope Detection
Envelope detection, also known as diode detection, is a straightforward method for demodulating AM signals. It relies on the fact that the envelope of an AM signal is proportional to the message signal.

The modulated signal is rectified using a diode, which essentially removes the negative component of the signal.

The resulting rectified signal is then low-pass filtered to smooth out the high-frequency components introduced during rectification.

The output of the low-pass filter represents the envelope of the original message signal.

Envelope detection is simple but effective and is commonly used in AM radio receivers.

5 – Synchronous Detection
Synchronous detection, also known as coherent detection, is a more sophisticated demodulation technique. It requires knowledge of the carrier signal’s frequency and phase.

The received modulated signal is mixed with a local oscillator signal at the carrier frequency. This mixing process shifts the carrier frequency down to baseband, resulting in a complex signal.

The complex signal is then low-pass filtered to obtain the real part, which represents the demodulated message signal. Synchronous detection is often used in high-performance AM demodulation and is more immune to noise and interference.

As you delve deeper into your lab session, remember that practical experience and experimentation play a significant role in mastering amplitude demodulation. By combining theoretical knowledge with hands-on practice, you’ll be well-equipped to tackle real-world challenges in signal processing and communication systems.

In the next session, we’ll look into Double SideBand Modulation.