Digital Communication MCQ Questions & Answers | ECE

A carrier is modulated by a digital bit stream having one of the possible phases of 0°, 90°, 180° and 270°. Then the modulation is termed as

The different access methods which permit many satellite users to operate in parallel through a single transponder without interfering with each other are
1. Frequency Division Multiple Access (FDMA)
2. Time Division Multiple Access (TDMA)
3. Code Division Multiple Access (CDMA)
Which of the above are correct?

The signal to noise ratio in telemetry should be

Four signals m₁(t) = cos(ω₀t), m₂(t) = 0.5cos(ω₀t), m₃(t) = 2cos(ω₀t) and m₄(t) = cos(4ω₀t) are multiplexed by time division multiplexing system. The commutator speed is

For a binary FSK signal with a mark frequency of 49 kHz, a space frequency of 51 kHz and an input bit rate of 2 kbps, the peak frequency deviation will be

A single bit, equally likely to be 0 and 1, is to be sent across an additive white Gaussian noise (AWGN) channel with power spectral density N₀/2. Binary signaling, with 0 → p(t) and 1 → q(t), is used for the transmission, along with an optimal receiver that minimizes the bit-error probability.
Let ϕ₁(t), ϕ₂(t), form an orthonormal signal set. If we choose p(t) = ϕ₁(t) and q(t) = -ϕ₁(t), we would obtain a certain bit-error probability P_b. If we keep p(t) = ϕ₁(t), but take q(t) = $$\sqrt {\text{E}} $$ ϕ₂(t), for what value of E would we obtain the same bit-error probability P_b?

In PCM, the signal-to-quantisation noise ratio for a sinusoidal signal quantized using 10-bit PCM is:

Six message signals, each of bandwidth 5 KHz, are time-division-multiplexed and transmitted. The signaling rate and minimum channel bandwidth to avoid cross-talk in TDM, respectively, are:

Eye pattern is

Match List-I with List-II and select the correct answer using the options given below-

List-I	List-II
a. Huffman	1. Elimination of redundancy
b. Error correcting	2. Reduces bit rate
c. NRZ-coding	3. Adapts the transmitted signal to the line
d. Delta modulation	4. Channel coding