Test: Electronic Devices & Digital Communications - 1 - Electronics and Communication Engineering (ECE) MCQ

What is the ratio of current for a forward bias of 0.05 V to the current for the same magnitude of reverse bias?

The probability of an electron being thermally promoted to the conduction band in Si(∈_g=1.107 eV) at room temperature (25°C)?

One curve of an n-channel MOSFET is characterized by the following parameters
I_D(sat) = 0.2 mA
V_Ds = 0.8 V

V_TN =0.8V

The value of conduction parameter is

Sampling rate needed to achieve (SNR)_0/P ≥ 45 dB with fs = 10 MHz in a PCM system. Find Sampling Rate

In a 64 step binary PCM system with a reference scale from 0 to 6.4 volts, the RMS quantization error will be,

In a BPSK signal detector, the local oscillator has a fixed phase error of 25.2°. Reduction in SNR will be by a factor of _____________

The SQR (Signal to Quantization Noise Ratio) of a system is 25.8 dB for 16 quantization levels. The percentage increase in SQR for 128 quantization levels is

Error distance in 8 QAM modulation scheme is

A system with transfer function H(s) is driven by a white noise x(t) with power density N₀. The Auto-correlation of the output signal is measured as    where α > 0. A possible transfer function H(s) for system wilt be

A vestigial SSB system is used to modulate a TV signal having bandwidth equal to 4 MHz. If roll-off factor is 1, the bandwidth required to transmit the signal is given by _________ MHz

The capacitance of varactor varies from 5 to 50 pF. Two such varactor diodes are used in the tunning circuit shown in figure 

If L= 10 mH, the tuning range of the circuit

The variation of drain current with gate to source voltage (lD - VGS characteristic) of a MOSFET is shown in figure. The MOSFET is