Wireless Comunication Simulations what are the correct answe

  
Wireless Comunication: Simulations
what are the correct answers? Process?

Problem 6. (20 points). Topic: Delta Modulation Consider the DM modulation Simulink model. The input signal is m(r), presented below. 0.0 Find the ratio m pkm for a given signal m p/km (t)» a If the first harmonic (fo) of this signal is a reference component (with max amplitude), and the bandwidth of this signal is 3fo find the parameter of the Simulink blocks \"Sampler\" (f,DA), if S/N is 17 dB 410 si H

Solution

A delta modulation (DM or -modulation) is an A/D and D/A conversion technique used for transmission of voice information where quality is not of primary importance. DM is the simplest form of differential pulse code modulation (DPCM) where the difference between successive samples are encoded into n-bit data streams. In delta modulation, the transmitted data are reduced to a 1-bit data stream. Its main features are:

·         The analog signal is approximated with a series of segments.

·         Each segment of the approximated signal is compared to the original analog wave to determine the increase or decrease in relative amplitude.

·         The decision process for establishing the state of successive bits is determined by this comparison.

·         Only the change of information is sent, that is, only an increase or decrease of the signal amplitude from the previous sample is sent, whereas a no-change condition causes the modulated signal to remain at the same 0 or 1 state of the previous sample.

Output signal power

In delta modulation there is a restriction on the amplitude of the input signal, because if the transmitted signal has a large derivative (abrupt changes) then modulated signal can not follow the input signal and slope overload occurs. Lets say if the input signal is

     

Modulated Signal (derivative of the input signal) which is transmitted by the modulator

Whereas the condition to avoid slope overload is

     

So the maximum amplitude of the input signal can be

    ==>      

Where f_s is the sampling frequency and is the frequency of the input signal and is step size quantization. So A_max is the maximum amplitude that DM can transmit without causing the slope overload and the power of transmitted signal depends on the maximum amplitude.

As per input signal m(t), A =1, , w = 1/0.01hz =100hz then fs=100hz