EC GATE 2008 - Online Test

Q1. At 20 GHz, the gain of a parabolic dish antenna of 1 meter and 70% efficiency is
Answer : Option D
Explaination / Solution:



Q2.
Noise with double-sided power spectral density on K over all frequencies is passed through a RC low pass filter with 3 dB cut-off frequency of fc. The noise power at the filter output is
Answer : Option C
Explaination / Solution:



Q3. Consider a Binary Symmetric Channel (BSC) with probability of error being p. To transmit a bit, say 1, we transmit a sequence of three 1s. The receiver will interpret the received sequence to represent 1 if at least two bits are 1. The probability that the transmitted bit will be received in error is
Answer : Option D
Explaination / Solution:
No Explaination.


Q4. Four messages band limited to W,W,2W and 3W respectively are to be multiplexed using Time Division Multiplexing (TDM). The minimum bandwidth required for transmission of this TDM signal is
Answer : Option D
Explaination / Solution:

Bandwidth of TDM is = 1/2 (sum of Nyquist Rate) = 1/2 [2W + 2W + 4W + 6W] = 7W

Q5.
Consider the frequency modulated signal with carrier frequency of 105 Hz. The modulation index is
Answer : Option B
Explaination / Solution:



Q6. The signal  is
Answer : Option C
Explaination / Solution:
No Explaination.


Q7. A speed signal, band limited to 4 kHz and peak voltage varying between +5 V and -5 V, is sampled at the Nyquist rate. Each sample is quantized and represented by 8 bits. If the bits 0 and 1 are transmitted using bipolar pulses, the minimum bandwidth required for distortion free transmission is
Answer : Option B
Explaination / Solution:



Q8.
In the following network, the switch is closed at t = 0- and the sampling starts from t = 0. The sampling frequency is 10 Hz.

The samples x(n), n = (0, 1, 2, ...) are given by
Answer : Option B
Explaination / Solution:
No Explaination.


Q9.
In the following network, the switch is closed at t = 0- and the sampling starts from t = 0. The sampling frequency is 10 Hz.

The expression and the region of convergence of the z -transform of the sampled signal are
Answer : Option C
Explaination / Solution:



Q10. An 8085 executes the following instructions 2710 LXI H, 30A0 H 2713 DAD H 2414 PCHL All address and constants are in Hex. Let PC be the contents of the program counter and HL be the contents of the HL register pair just after executing PCHL. Which of the following statements is correct ?
Answer : Option C
Explaination / Solution:

2710H LXI H, 30A0H ; Load 16 bit data 30A0 in HL pair 2713H DAD H ; 6140H ⟶ HL 2714H PCHL ; Copy the contents 6140H of HL in PC Thus after execution above instruction contests of PC and HL are same and that is 6140H