Showing posts with label pulse modulation. Show all posts
Showing posts with label pulse modulation. Show all posts

## 1 Sept 2018

### Types of Modulation (Classification of Modulation)

Here we will discuss what is modulation and different types of modulation.
So let's first see the definition of modulation and it's classification -

## Definition of Modulation

Modulation is a process by which some characteristic (amplitude/frequency or phase) of a high frequency carrier wave is varied in accordance with the instantaneous value of the message signal (modulating signal).

Now we will see the classification of modulation-

## Types of Modulation

 Types of Modulation

Modulation can be classified broadly into two types -
*Continuous wave modulation
*Pulse modulation

## Continuous Wave Modulation

In this type of modulation the carrier wave is continuous. Continuous wave modulation is a technique of modulation where some parameter (amplitude, frequency or phase) of a sinusoidal carrier is varied in accordance with the instantaneous value of the modulating signal.

## (adsbygoogle = window.adsbygoogle || []).push({}); Pulse Modulation

In the pulse modulation the carrier wave is in the form of pulses. In Pulse modulation some parameter (amplitude, width or position) of the pulsed carrier wave is varied as per the instantaneous value of the modulating signal.

The continuous wave modulation can again be classified into two types-
*Amplitude Modulation (AM)
*Angle Modulation

Amplitude Modulation

 Message Signal and the Carrier Wave

 Amplitude Modulated Wave (AM Signal)

In amplitude modulation the amplitude of the carrier wave is varied according to the instantaneous value of the modulating (message) signal. Therefore the information is present in the amplitude variations of the carrier wave.

Angle Modulation
It may be defined as the process in which the total phase angle of a carrier wave is varied in accordance with the instantaneous value of the modulating signal.

The Angle modulation is again of two types-
*Frequency Modulation (FM)
*Phase Modulation (PM)

Frequency Modulation

 Frequency Modulation (FM)

In frequency modulation, the frequency of the carrier wave is varied in accordance with the instantaneous value of the modulating signal.

Phase modulation

 Phase Modulation (PM)

In Phase modulation, the phase of the carrier wave is varied according to the instantaneous value of the modulating signal (message signal).

Now let's discuss the pulse modulation

Pulse Modulation
In Pulse modulation some parameter (amplitude, width or position) of the pulsed carrier wave is varied as per the instantaneous value of the modulating signal.

Pulse modulation is of 3 types
*Pulse Amplitude Modulation (PAM)
*Pulse Width Modulation (PWM)/Pulse Duration Modulation (PDM)
*Pulse Position Modulation (PPM)

Pulse Amplitude Modulation

 Pulse Amplitude Modulation (PAM)

In pulse amplitude modulation, the amplitude of the pulsed carrier wave is varied according to the modulating signal value.

Pulse Width Modulation

 Pulse Width Modulation (PWM)/Pulse Duration Modulation (PDM)

In this type of modulation, the width of the pulsed carrier is varied as per the value of the modulating signal

Pulse Position Modulation

 Pulse Position Modulation (PPM)

In Pulse position modulation, the position of the pulsed carrier is varied as per the value of the modulating signal.

# Advantages of Pulse Code Modulation (PCM)

1.Very high noise immunity

2.In pulse code modulation repeaters are used between the transmitter and receiver. Repeaters are used to regenerate the received PCM signal. Use of repeaters is possible due to digital nature of the signal.

3.Effect of noise is further reduced due to the use of repeaters.

## 16 Oct 2017

### PULSE POSITION MODULATION (PPM) - Basics, Definition and Waveform of PPM

Pulse modulation can be categorized broadly into two types-
#Analog modulation and
#Digital modulation
The analog pulse modulation can again be of two types-

# Pulse Position Modulation Video [HD]

#Pulse Amplitude Modulation (PAM)
#Pulse Time Modulation (PTM)
The Pulse Time Modulation (PTM) can further be classified into two types of modulation-
#Pulse Width Modulation (PWM)/Pulse Duration Modulation (PDM)
#Pulse Position Modulation (PPM)
Pulse Code Modulation (PCM) is a digital pulse modulation technique.

# What is Pulse Modulation

Pulse modulation is a type of modulation where some parameter of the pulsed carrier wave is varied as per the instantaneous value of the modulating signal (message signal).

## Types of Pulse Modulation Techniques

Pulse modulation can be categorized into 3 types-

2.Pulse Width Modulation (PWM)

Out of these three types of pulse modulation techniques, PWM and PPM come under Pulse Time Modulation (PTM).

# Pulse Width Modulation Video [HD]

## Pulse Time Modulation (PTM)

In pulse time modulation, the timing of pulses of the pulsed carrier is varied. So the variations occur on the time axis. Since it is of two types, Pulse Width Modulation and Pulse Position Modulation, where width and position of the pulses is varied respectively. These changes in width or position take place on the time axis. Therefore PWM and PPM are types of pulse time modulation.

ðŸŒ“READ THIS ALSO:-
COMPARISON OF PAM, PWM, PPM MODULATION TECHNIQUES

Now we will understand the Pulse Width Modulation (PWM), in detail-

## (adsbygoogle = window.adsbygoogle || []).push({}); Pulse Width Modulation (PWM)

### Definition:-

In Pulse width modulation, width (duration) of the pulses of the carrier wave is varied according to the modulating signal (message signal).
Let's analyze the waveform of pulse width modulation.
Look at the image given below to see the waveform of pulse width modulated signal. (Click the image to enlarge)-

 Pulse Width Modulation Waveform (PWM)

Here you can see waveforms of modulating signal, pulsed carrier wave and pulse width modulated wave.

ðŸŒ“READ THIS ALSO:-

#PULSE CODE MODULATION (PCM) [ADVANTAGES AND DISADVANTAGES]
#Quadrature Amplitude Modulation (QAM)/ QAM Transmitter and QAM Receiver Block Diagram

As per the definition of pulse width modulation, we know that, in Pulse width modulation, the width of the pulses of carrier wave is varied according to the message signal. So you can see here in the image that as the amplitude of the message signal changes, the width of pulses of the pulsed carrier wave changes accordingly.
You can easily observe here, the width of the pulse is maximum when amplitude of the message signal is at maximum and in the same way, width is minimum when amplitude of the modulating signal is minimum.

## (adsbygoogle = window.adsbygoogle || []).push({}); Important Observations about Pulse Width Modulation (PWM)

1.Since it is pulse width modulation (pulse duration modulation), therefore only the width (duration) of the pulses of the carrier wave changes. No change takes place in amplitude or position of the pulses.

ðŸŒ“READ THIS ALSO:-

#Watch the VIDEOS PLAYLIST here (Pulse modulation Techniques)

2.As the width of pulses changes according to the modulating signal; information is present only in the width of the pulses. In Pulse width modulation, amplitude or position of the pulses contain no information.

## Properties of Pulse Width Modulation (PWM)

#### 1.Power in PWM

In PWM, instantaneous power of the transmitter varies due to variations in width of the pulses.

#### 2.Noise in PWM

Pulse Width Modulation is less affected by noise due to its constant amplitude. It is also easier to remove noise from the signal as compared to Pulse amplitude modulation.

## 14 Oct 2017

### PULSE AMPLITUDE MODULATION (PAM) || Definition, Basics and Waveform of PAM Explained

In this post we will discuss Pulse Amplitude Modulation (PAM). Pulse Amplitude Modulation is a pulse modulation technique. Other techniques of analog pulse modulation are- Pulse Width Modulation (PWM) and Pulse Position Modulation (PPM). But before discussing pulse amplitude modulation, it is important to know, what is pulse modulation and how it is different from continuous wave modulation.

ðŸŒ“READ THIS ALSO:-
#NEED AND BENEFITS OF MODULATION

# Difference between Pulse Modulation and Continuous Wave Modulation

In pulse modulation, some parameter (amplitude, width or position) of the pulsed carrier wave is varied as per the instantaneous value of the modulating signal (message signal). Types of analog pulse modulation techniques are- Pulse Amplitude Modulation (PAM), Pulse Width Modulation (PWM) and Pulse Position Modulation (PPM).
While continuous wave modulation is a technique of modulation where some parameter (amplitude, frequency or phase) of a sinusoidal carrier is varied in accordance with the instantaneous value of the  modulating signal.

ðŸŒ“READ THIS ALSO:-
COMPARISON OF PAM, PWM, PPM MODULATION TECHNIQUES

Types of continuous wave modulation are- Amplitude modulation (AM), Frequency Modulation (FM) and Phase Modulation (PM).
See the image given below to understand different types of modulation techniques. Click the image to enlarge it-

## Classification of Modulation Techniques

The definitions of PAM, PWM and PPM are given below for quick reference-

## Pulse Amplitude Modulation (PAM)

In pulse amplitude modulation, the amplitude of pulsed carrier wave is varied according to the modulating signal.

## Pulse Time Modulation (PTM)

In pulse time modulation, the timing of pulses of the pulsed carrier is varied. Therefore the variations in the pulse are on the time axis.

Pulse Time Modulation (PTM) is of two types-
Pulse Position Modulation (PPM)

## Pulse Width Modulation (PWM)

In PWM, the width of pulsed carrier wave is varied as per the instantaneous value of the modulating signal.

## Pulse Position Modulation (PPM)

In PPM, the position of pulsed carrier is varied as per the modulating signal (message signal).

Now we understand the basic difference between PAM, PWM and PPM. Now it's time to discuss pulse Amplitude Modulation in some detail-

# Pulse Amplitude Modulation (PAM)

## Definition:-

The modulation technique in which the instantaneous amplitude of the pulsed carrier is varied according to the modulating signal (message signal) is called as pulse amplitude modulation (PAM).

## Waveform of Pulse Amplitude Modulation (PAM)

Look at the image given below carefully to understand the formation of pulse amplitude modulated wave. (Click the image to enlarge)-

 Pulse Amplitude Modulation (PAM) Waveform

Here in this image, you can see, three waveforms.

ðŸŒ“READ THIS ALSO:-
#SAMPLING THEOREM AND RECONSTRUCTION (SAMPLING AND QUANTIZATION)
#Watch the VIDEOS PLAYLIST here (Pulse modulation Techniques)

The first waveform is of modulating signal (message signal), the second one is of the pulsed career wave and the third waveform is of the pulse amplitude modulated wave (PAM).
The message signal can have multiple frequencies and variable amplitude. Here we have used a sinusoidal message signal. The carrier wave that we have used here, is a train of pulses having high frequency. Since we know that in Pulse modulation, the carrier wave is in the form of pulses.
Now we will understand how can we make pulse amplitude modulated wave (PAM).

ðŸŒ“READ THIS ALSO:-

#AMPLITUDE MODULATION (TIME DOMAIN EQUATIONS AND WAVEFORMS)
#FREQUENCY SPECTRUM OF AMPLITUDE MODULATION (WAVEFORMS AND EQUATIONS DERIVATION)

As we have discussed that in Pulse amplitude modulation, the instantaneous amplitude of the pulsed carrier is varied according to the modulating signal (message signal). Now look at the image shown above very carefully, observe that, as the amplitude of the modulating signal (message signal or baseband signal) increases, the amplitude of the pulsed carrier wave increases and becomes maximum when the amplitude of the modulating signal reaches at its maximum. Now the amplitude of the carrier wave starts decreasing with decrease in amplitude of the modulating signal. So it is clear from the image that the amplitude of the pulsed carrier wave varies according to the instantaneous value of the message signal.

## Important Observations about Pulse Amplitude Modulation (PAM)

#As it is Pulse Amplitude Modulation (PAM), therefore only the amplitude of the pulsed carrier changes.
#There is no change in the width or position of the pulsed carrier wave. So the width and position of the carrier wave pulse is constant here.

ðŸŒ“READ THIS ALSO:-

#Digital Modulation Techniques (ASK, FSK, PSK, BPSK)/ Amplitude, Frequency and Phase Shift Keying

### COMPARISON OF PAM, PWM, PPM MODULATION TECHNIQUES

In the last post we discussed different types of pulse modulation techniques, like Pulse Amplitude Modulation (PAM), Pulse Width Modulation (PWM), Pulse Position Modulation (PPM) and Pulse Code Modulation (PCM).
In this post we will deal with the comparative study of PAM, PWM and PPM.
Here we will compare these 3 different pulse modulation techniques, on the basis of various parameters.

# Comparison of PAM, PWM and PPM Modulation Techniques Video [HD]

## 1.Definition of PAM, PWM and PPM

PAM- In pulse amplitude modulation, the amplitude of the pulsed carrier wave is varied according to the modulating signal value.
PWM- In pulse width modulation, the width of pulsed carrier is varied as per the value of the modulating signal.
PPM- In pulse position modulation, the position of the pulsed carrier is varied as per value of modulating signal.

## 2.Waveform of PAM, PWM and PPM

Waveform of PAM, PWM and PPM is given in the image below. Click on the image to enlarge it.

 Comparison of PAM, PWM, PPM Waveforms

PAM- Amplitude
PWM- Width
PPM- Position

## (adsbygoogle = window.adsbygoogle || []).push({}); 4.Where the Information is Present in PAM, PWM and PPM

PAM- In amplitude variations of the pulses
PWM- In width variations of the pulses
PPM- In position variations of the pulses

## 5.Type of Carrier Wave Used in PAM,PWM and PPM

PAM- Train of pulses
PWM- Train of pulses
PPM- Train of pulses

ðŸŒ“READ THIS ALSO:-
#PULSE MODULATION TECHNIQUES (PAM, PWM, PPM, PCM)

## 6.Bandwidth of PAM, PWM and PPM

PAM- Bandwidth depends on the width of the pulse
Bandwidth requirement is low
PWM- Bandwidth of the channel depends on rise time of the pulse
Bandwidth requirement is high
PPM- Bandwidth depends on rise time of the pulse
Bandwidth requirement is high

## 7.Instantaneous Power in PAM, PWM and PPM

PAM- Power varies due to change in amplitude of the pulses
PWM- Instantaneous power varies due to change in width of the pulses
PPM- Instantaneous power is constant due to constant amplitude and width of the pulses

## 8.Noise Interference in PAM, PWM and PPM

PAM- Noise interference is maximum and it is difficult to remove noise
PWM- Noise interference is less due to constant amplitude
PPM-  Noise interference is less due to constant amplitude

## (adsbygoogle = window.adsbygoogle || []).push({}); 9.Similarity of PAM, PWM and PPM With Continuous Wave Modulation

PAM- Similar to Amplitude Modulation (AM)
PWM- Similar to Frequency Modulation (FM)
PPM- Similar to Phase Modulation (PM)

## 10.Synchronization Between Transmitter And Receiver in case of PAM, PWM and PPM

PAM- Synchronization between transmitter and receiver is not required.
PWM- In this case too no need of any synchronization
PPM- In Pulse position modulation synchronization is required. The transmitter sends synchronizing pulses.

Read More-

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FREQUENCY SPECTRUM OF AMPLITUDE MODULATION (WAVEFORMS AND EQUATIONS DERIVATION)

AMPLITUDE MODULATION (TIME DOMAIN EQUATIONS AND WAVEFORMS)

ADVANTAGES AND DISADVANTAGES OF DIGITAL COMMUNICATION SYSTEM

ADVANTAGES OF OPTICAL FIBER COMMUNICATION

STEP INDEX OPTICAL FIBER (MULTIMODE AND SINGLE MODE STEP INDEX FIBERS)

PULSE MODULATION TECHNIQUES (PAM, PWM, PPM, PCM)

OPTICAL FIBER: STRUCTURE AND WORKING PRINCIPLE

PULSE AMPLITUDE MODULATION (PAM)

COMPARISON OF PAM, PWM, PPM MODULATION TECHNIQUES

PULSE WIDTH MODULATION (PWM)

CONTINUOUS TIME AND DISCRETE TIME SIGNALS (C.T. AND D.T. SIGNALS)

NEED AND BENEFITS OF MODULATION

PULSE POSITION MODULATION (PPM)

OPTICAL FIBERS IN COMMUNICATION: COVERS ALL IMPORTANT POINTS

OPTICAL FIBER SOURCES (DESIRABLE PROPERTIES)

AMPLITUDE MODULATION Vs FREQUENCY MODULATION (ADVANTAGES AND DISADVANTAGES)

PULSE CODE MODULATION (PCM) [ADVANTAGES AND DISADVANTAGES]

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Quadrature Phase Shift Keying Modulation (QPSK) Basics, Waveform and Benefits

Pulse Code Modulation (PCM) Vs Differential Pulse Code Modulation (DPCM)