Digital Communication MCQ Questions & Answers | ECE

Time division multiplexing (TDM) is possible with

The PSD of the Manchester line code

What is the required bandwidth of a PCM system for 256 quantization levels when 48 telephone channels, each band limited to 4 kHz, are to be time-division multiplexed by this PCM?

The temperature at a particular place varies between 14°C and 34°C. For the purpose of transmitting the temperature record of that place using PCM, the record is sampled at an appropriate sampling rate and the samples are quantized. If the error in representation of the samples due to quantization is not to exceed ±1% of the dynamic range, what is the minimum number of quantization levels that can be used?

24 voice signals are sampled uniformly at 8 kHz and then sent using TDM scheme. The sampling process uses flat-top samples with 1 µs duration. An extra pulse of duration 1 µs is added for the purpose of synchronization. The spacing between two consecutive pulses is-

The quantization of a PCM system depends on

In asynchronous TDM, for n signal sources, each frame contains m slots, where m is usually

In a PCM system, if the code word length is increases form 6 to 8 bits, the signal to quantization noise ratio improves by the factor

A source emits bit 0 with probability $$\frac{1}{3}$$ and bit 1 with probability $$\frac{2}{3}.$$ The emitted bits are communicated to the receiver. The receiver decides for either 0 or 1 based on the received value R. It is given that the conditional density functions of R as
\[\begin{array}{l} {f_{R/0}}\left( r \right) = \left\{ {\begin{array}{*{20}{c}} {\frac{1}{4},}&{ - 3 \le r \le 1}\\ {0,}&{{\rm{otherwise}}} \end{array}} \right.\,{\rm{and}}\\ {f_{R/1}}\left( r \right) = \left\{ {\begin{array}{*{20}{c}} {\frac{1}{6},}&{ - 1 \le r \le 5}\\ {0,}&{{\rm{otherwise}}} \end{array}} \right. \end{array}\]
The minimum decision error probability is

Discrete samples of an analog signal are uniformly quantized to PCM. If the maximum value of analog sample is to be represented within 0.1% accuracy, then the minimum number of binary digits required per sample is