Question

Jor preparation Questions to get 4 1. What is the spectrum of the signal? 2. What is the channel bandwidth and how is it calculated? 3. What is the signal spectrum width and how is it calculated? 4. For what purpose the modulation in telecommunication systems is used? 5. How the orthonormal functions are used for the signal description? 6. You will be given a picture if the signal. Your task will be to determine: Whether signal is periodic or non-periodic. Whether signal is continuous in time or discrete in time 7. What can You calculate using the Fourier transformations? 8. What type of the Fourier transformation it is necessary to use for the deterministic periodic analog signal? Name, formula and the description of the letters in formula 9. What type of the Fourier transformation it is necessary to use for the deterministic non-periodic analog signal? Name, formula and the description of the letters in formula 10. What type of the Fourier transformation it is necessary to use for the deterministic periodic discrete signal? Name, formula and the description of the letters in formula

Answer 1

1. Fourier theory says that any waveform can be represented by a summation of a number of sinusoids, each with a particular amplitude and phase. Such a representation is referred to as the signal's spectrum. It is basically the frequency domain representation of the waveform.

2. Channel bandwidth is the frequency range that constitutes the channel in it. Let's take an example of AM transmission, suppose the carrier frequency is Fc Hz and the message frequency is Fm Hz. Then the channel bandwidth is 2Fm Hz.

It can be calculated using the spectrum of the signal. It is basically the difference between the first and the last component of the frequency.

3. Spectral width is the wavelength interval over which the magnitude of all spectral components is equal to or greater than a specified fraction of the magnitude of the component having the maximum value.

It can be calculated using the -3 db method, FWHM method.

4. Modulation allows us to send multiple signals over a bandpass frequency range. If every signal uses its own frequency range then the overall bandwidth will increase drastically.

It is also used to decrease the transmitting antenna size. It shifts the baseband signal to a much higher frequency which in result decreases the antenna size.