Why Is Flat Top sampling preferred?
In flat top sampling the top of samples are constant and are equal to instantaneous value of the signal while a more practical method of sampling is natural sampling in which the width of pulse is finite.
Why Is Flat Top sampling more commonly used compared to natural sampling?
Flat top sampling is like natural sampling i.e; practical in nature. In comparison to natural sampling flat top sampling can be easily obtained. In this sampling techniques, the top of the samples remains constant and is equal to the instantaneous value of the message signal x(t) at the start of sampling process.
What is difference between natural PAM and Flat Top PAM?
In natural PAM, a signal sampled at Nyquist rate can be reconstructed, by passing it through an efficient Low Pass Filter (LPF) with exact cutoff frequency. Though the PAM signal is passed through a LPF, it cannot recover the signal without distortion. Hence, to avoid this noise, use flat-top sampling.
How is flat top PAM generated?
Pulse Modulation is mainly used for transmitting analog data like data otherwise continuous speech signal. A PAM is generated from a pure sine wave modulating signal and a square wave generator which produces the carrier pulse and a PAM modulator circuit.
What differentiates flat top sampling and natural sampling?
The difference between natural sampling and flat top sampling is that: In natural sampling the analog input is multiplied by a train of uniformly spaced, rectangular pulses. While in flat top sampling the top of the samples are flat, this means they have a constant amplitude.
What is the disadvantage of Flat Top sampling?
What is the main disadvantage of Flat top sampling? The sampling rate is large in proportion with f. This has practical limitations. The sampled signal spectrum has spectral gaps.
What is the error introduced in Flat Top sampling *?
In flat-top sampling, due to the lengthening of the sample, amplitude distortion and delay are introduced. This distortion is referred to as the aperture effect and occurs during the reconstruction of g(t) form s(t).
Why PAM is not preferable in digital transmission?
PAM is essentially AM, but quantized in both time and amplitude. The most prominent disadvantage of PAM is that most transmission mediums exhibit some ‘loss’, and so the received pulse stream will be distorted in terms of amplitude — which means, in turn, that the received information may be distorted as well!
Why sampling is used in communication?
To convert a signal from continuous time to discrete time, a process called sampling is used. The value of the signal is measured at certain intervals in time. If the signal contains high frequency components, we will need to sample at a higher rate to avoid losing information that is in the signal.
What differentiate flat top sampling and natural?
What is aperture effect in Flat Top sampling?
The amplitude of the flat top signal must be constant, but sometimes it is not constant due to the high frequency roll off of the sampling signal. Thus the sampled signal in the flat top sampling consists of attenuated high frequency components and this effect is known as Aperture effect.
What are the different types of Pam sampling techniques?
There are two types of sampling techniques for transmitting a signal using PAM. They are: Flat Top PAM: The amplitude of each pulse is directly proportional to modulating signal amplitude at the time of pulse occurrence. The amplitude of the signal cannot be changed with respect to the analog signal to be sampled.
Why is flat-top sampling done?
Hence to avoid this noise, flat-top sampling is done as shown in the following figure. Flat-top sampling is the process in which sampled signal can be represented in pulses for which the amplitude of the signal cannot be changed with respect to the analog signal, to be sampled. The tops of amplitude remain flat.
Why flat top sampling is preferred in pulse amplitude modulation?
Hence, flat top sampling is preferred in pulse amplitude modulation. As we can see it consist of a low pass filter, a modulator along with a train generator and a pulse reshaping circuit. Here the modulating signal is given to the low pass filter in order to band limit the message signal.
Does Pam modulator perform natural sampling?
However, in the block diagram, we have seen the modulator is performing natural sampling. Another important aspect that is to be considered while generating and transmitting PAM signal is its bandwidth utilization. So, lets now discuss the transmission bandwidth utilized by PAM signal.