# 24 an am signal has the equation v f 15 3 t sin 465

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24) An AM signal has the equation v ( f ) = [ 15 + 4sin ( 44 10 3 t ) ] sin ( 46.5 10 6 t ) V (a) Find the carrier frequency. 6
(b) Find the frequency of the modulating signal.
(c) Find the value of m .
(d) Find the peak voltage of the unmodulated carrier.
(e) Sketch the signal in the time domain, showing voltage and time scales. 30) An audio system requires a frequency response from 50 Hz to 15 kHz for high fidelity. If this signal were transmitted using AM, what bandwidth would it require?
33) An AM signal has the following characteristics: f c = 150 MHz f m = 3 kHz E c = 50 V E m = 40 V For this signal find: (a) the modulation index
m = E m / E c = 40 V/50 V = 0.8 (b) the bandwidth 2 f m = 2*3 kHz = 6 kHz (c) the peak voltage for the upper side frequency E usb = mE c 2 = 0.8 50 V 2 = 40 V 2 = 20 V 48) An AM CB transmitter with a carrier frequency of 27.005 MHz is connected as shown in Figure 3.22(a). the oscilloscope display is shown in Figure 3.22(b). sketch the same signal as it would appear on the spectrum analyzer.