What is Overmodulation in PWM?

What is Overmodulation in PWM?

A compensated modulation technique (CMT) adaptable to continuous and discontinuous modulators eliminates the voltage error and transitions to six-step operation without inducing a voltage transient. The CMT applies to voltage and current regulated PWM inverters employing most of the modern switching strategies.

Does modulating signal has low frequency?

Amplitude Modulation vs Frequency Modulation Amplitude Modulation index ranges from 0 to 1, requires low bandwidth in the range of 10 kHz, operates in medium and high frequency ranges of 535 to 1705 Kilohertz, has a simple circuit with only two side bands, and receives low quality signals with poor sound quality.

What causes over-modulation?

A new method for preventing spurious sidebands. The cause of over-modulation splatter is the sudden break in the modulation envelope when the carrier is swung down to the zero axis. Here is a system that fills in the over modulation “gaps” in the carrier and thereby prevents generation of spurious sidebands.

What is meant by modulating?

Modulation is the process of converting data into radio waves by adding information to an electronic or optical carrier signal. A carrier signal is one with a steady waveform — constant height, or amplitude, and frequency.

Why over-modulation should be avoided?

As you will remember, it is very important to avoid over-modulation. This would distort the amplitude modulated signal and cause undue bandwidth and interference. If over-modulation does occur the carrier is chopped up and the modulation no longer resembles its modulating signal.

What happens if signal is over modulated?

Overmodulation results in spurious emissions by the modulated carrier, and distortion of the recovered modulating signal. This means that the envelope of the output waveform is distorted.

How does modulation improve quality of reception?

The attenuation reduces with increase in frequency of the transmitted signal, and they travel longer distance . The modulation process increases the frequency of the signal to be transmitted . Therefore, it increases the range of communication.

Why Overmodulation should be avoided?

What is a modulating effect?

Modulation effects are a particular category of audio effect (FX). These are effects which modify the sound in a certain way: by adding a time-delayed version of the sound to itself, and then varying the size of that delay over time.

Why Overmodulation is undesirable in AM?

So when m is greater than one, over-modulation occurs and the modulating signal being of greater amplitude,part of its information is lost in the process of modulation which is undesirable. The resulting waveform looks like below, the gaps indicating part of modulating signal that is lost.

When does overmodulation occur in an AM modulator?

Overmodulation •Overmodulationis a condition that occurs when an excessive intelligence signal overdrives an AM modulator making %m > 100% (because E i>E c •Modulated carrier amplitude reach value greater than double of unmodulated value

Why is over modulation not important in FM?

Over modulation isn’t really of any significance to FM systems (unlike AM). If the modulation signal amplitude is too great, any decent frequency modulator will limit the signal so that it can’t push the bandwidth of the modulated signal too wide in the frequency spectrum.

How does overmodulation affect the output waveform?

Overmodulation results in spurious emissions by the modulated carrier, and distortion of the recovered modulating signal. This means that the envelope of the output waveform is distorted.

What happens to the carrier signal during modulation?

In effect, the modulating signal becomes clipped. With amplitude modulation, the carrier signal is alternately driven above and below its resting (unmodulated) value. At 100% modulation, the peaks will be driven to twice the resting power, and the “valleys” will reach zero.