PYQs Based Test - 09 : Communication and Optical Instrumentation

An amplitude modulation (AM) scheme uses tone modulation, with modulation index of 0.6. The power efficiency of the AM scheme is _______ % (rounded off to one decimal place)

When the movable arm of a Michelson interferometer in vacuum (n = 1) is moved by 325 μm, the number of fringe crossings is 1000. The wavelength of the laser used in nanometers is ____.

A sinusoid of 10 kHz is sampled at 15 k samples/s. The resulting signal is passed through an ideal low pass filter (LPF) with cut-off frequency of 25 kHz. The maximum frequency component at the output of the LPF (in kHz) is

A light detector circuit using an ideal photo-diode is shown in the figure. The sensitivity of the photo-diode is 0.5 μA/μW. With Vᵣ = 6 V, the output voltage Vₒ = −1.0 V for 10 μW of incident light. If Vᵣ is changed to 3 V, keeping all other parameters the same, the value of Vₒ in volts is __________V.

The photo diode in the figure below has an active sensing area of 10 mm², a sensitivity of 0.5 A/W and a dark current of 1 µA. The i-to-v converter has a sensitivity of 100 mV/µA. For an input light intensity of 4 W/m², the output V${}_O$ in volt is ____.