Problem 2: Consider a DSB-SC system: modulating signal: m(t)= 2 cos4000 πt +5 cos 6000 Jit carrier signal: c(t) = 100 cos 257fct where f= 50kHz. Determine and sketch the spectrum of the modulated signal.

Modify this circuit to extend the upper frequency limit to greater than 15 MHz. You may change the topology (i.e. configuration), but not the power supply voltage or collector bias current. The circuit voltage gain must be 46dB +/- 1 dB. Provide simulation results to show AC frequency responses of both circuits on the same plot, and annotate the 3dB upper frequency limit on both traces. Use typical ẞ values from the data sheet for the simulation. You may assume that 1% resistors are available in values below 100. The circuit must adhere to Standard Bias techniques. V4 Rser=0 SINE(0 0.02 10k) AC 1 VCC ୯ V2 +15V Cin1 1μ -VCC VCC R4 Rc1 147k 7k Q3 2N3904 R7 R6 9.09 20.5k Ce1 Re1 1.00k 10p Out

A baseband signal has the spectrum sketched in the first image added below.   The baseband signal modulates a 98 kHz carrier sine wave. Using frequency and amplitude labelling similar to that in Figure 2, sketch the spectrum of the modulated signal using a template added in image 2, for the following modulations: i-AM with the amplitude of the carrier wave being 20 V   ii-DSBSC   iii-SSB – the lower sideband   iv-SSB – the upper sideband

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A carrier signal is amplitude modulated by a sinewave. The resulting AM waveform is shown below. 3.5V- 1V- a) What is the amplitude of the carrier signal? b) c) To achieve 75 percent modulation, what amplitude of the modulating signal is needed? d) Calculate the effective voltage of the AM signal What is the modulation index?

Question 3 a) For a single-frequency sine wave modulating signal of 3 kHz with a carrier frequency of 36 MHz, what is the spacing between sidebands? b) A carrier of 49 MHz is frequency-modulated by a 1.5-kHz square wave. The modulation index is 0.25. Sketch the spectrum of the resulting signal. (Assume only harmonics less than the sixth are passed by the system.)

Q2: Draw the output PSK waveform for the digital data: Input signal Carrier Input Q: What is the main benefit of measuring the scattering parameters of RF network?

If the maximum frequency deviation is 25kHz and modulating signal frequency is 12kHz.     6c.    Is this FM treated as narrow band or wide band?

Question 4. Select the statement that best describes the PM wave.a. Carrier phase angle changes represent the PM modulated signal, however, unlike FM and AM modulatedcarriers, it is not always easy to see these phase changes in the plot.b. The FM signal accurately represents the message.c. Although PM and FM techniques are classified as angular modulation techniques, they cannot be usedinterchangeably (i.e., modulated with FM and demodulated with PM, and visa versa).d. All statements are correct.

2. Determine the peak phase deviation and modulation index for a PM modulator with a deviation sensitivity K = 2.5 rad/V and a modulating signal v(t) = 2 cos (212000t). %3D