How Superhet Principle Leads to the Production of Selectivity in Receivers between the Signals - Assignment Example

Part 1: Section C

Question 1

From the output waveform obtained from the linear modulator, its spectrum diagram is obtained as follows;

The carrier frequency of the signal is obtained as;

The amplitude of the spectrum is obtained by equating its amplitude to half of that of the carrier signal. Thus,

Also, from the output spectrum, the message frequency is obtained as follows,

Thus, the output signal is expected to be observed at the point when the output signal is at the following frequencies;

Thus by considering the positive carrier frequency, the spectrum obtained was;

• For the DSB, the carrier frequency and the baseband frequencies are obtained as follows;

Baseband frequency

For the carrier frequency,

And for the case of SSB USB, the carrier and baseband frequency would have been;

• Effects on the demodulating signal on a local carrier having parts in will partially remove the carrier signal with some part remaining causing the output signal contains some part of the sending signal.

Also, if has a phase on the DSB, the modulated signal will not be affected by the phase because the detection of the amplitude-modulated signal is not affected by the angle at which the signal is delayed.

By tuning the local oscillator to 550 kHz, the capacitance of the local oscillator is obtained as;

By assuming that R=1k,

For the case of VHF, the restriction does not hold because the frequency level I perceived to be constant within the range of operation.

Question 3

• The character error rate is obtained as;

Also, on the side of the

• From the result obtained, it is observed that with an introduction of non-equal probability, the error rate would deviate from the actual value leading to the distortion of the signal highly.
• The inclusion of a parity bit in each code would not make any change in the error rate of the character.
• By use of two thresholds, the output signal would affect the error rate by reducing the chance of it occurring in the signal.
• In the case of cascading the n number of regenerators will lead to a reduction in the error rate of the signal transmitted.
• By considering the initial state at which the PREAMP is installed, the signal-to-noise ratio obtained was as follows;