What are the conditions for under perfect and Overmodulation?
What are the conditions for under perfect and Overmodulation?
It is called as Under-modulation. Such a wave is called as an under-modulated wave. If the value of the modulation index is greater than 1, i.e., 1.5 or so, then the wave will be an over-modulated wave.
Why rectifier is used in AM modulation?
Diode / rectifier – serves to pass one half of the received signal over the other. Low pass filter – required to remove the high frequency content that remains in the signal after detection / demodulation.
Why is it called synchronous detector?
In electronics, a synchronous detector is a device that recovers information from a modulated signal by mixing the signal with a replica of the un-modulated carrier. This can be locally generated at the receiver using a phase-locked loop or other techniques.
Why does AM have bandwidth?
The bandwidth of an amplitude modulated signal is of importance for many reasons. The amplitude modulation, AM bandwidth is important when designing filters to receive the signals, determining the channel spacing, and for a number of other reasons.
What is bandwidth of AM modulation?
Four times the signal frequency.
Why filter is used in rectifier?
The filter is a device that allows passing the dc component of the load and blocks the ac component of the rectifier output. Thus the output of the filter circuit will be a steady dc voltage.
Why do we need rectifier?
A rectifier is used for powering appliances Using a rectifier in the power supply helps in converting AC to DC power supply. Bridge rectifiers are widely used for large appliances, where they are capable of converting high AC voltage to low DC voltage.
What is the condition in synchronous detection?
Synchronous demodulation picks out a weak signal at 1 kHz in the presence of strong noise sources at 50 Hz and 2.5 kHz. Any noise components that are close to the signal of interest will appear at frequencies close to dc so it is important to pick a modulation frequency that does not have strong noise sources near it.
What is overmodulation?
Overmodulation. Overmodulation is the condition that prevails in telecommunication when the instantaneous level of the modulating signal exceeds the value necessary to produce 100% modulation of the carrier. In the sense of this definition, it is almost always considered a fault condition. In layman’s terms, the signal is going “off the scale”.
How does am over modulation affect the phase of a signal?
AM over modulation causes the carrier wave to invert it’s phase when the modulating signal has an amplitude that is above a certain level. Broadcast AM typically never does this because the complexity of an accurate demodulator is too great for the thousands and millions of receivers.
What does 100% modulation mean?
100% modulation is where the modulating signal drives the carrier to zero and is theoretically the maximum modulation that can be successfully demodulator by a regular AM envelope detector. Over modulation isn’t really of any significance to FM systems (unlike AM). If the modulation signal amplitude is too great,…
What is modulation in wireless communication?
Modulation is nothing but increasing strength of the signal , and a specific signal leave is required called carrier signal , if carrier signal excised call over and below which called under modulation , both should not occurre in practice.