Twenty-four voice signals are sampled uniformly and then time-division multiplexed. The sampling operation uses flat-top samples (Natural Sampling) with 1 μs duration. The multiplexing operation includes provision for synchronization by adding an extra pulse of sufficient amplitude and also 1 μs duration. The highest frequency component of each voice signal is 3.4 kHz.

a) Assuming a sampling rate of 8 kHz, calculate the spacing between successive pulses of the multiplexed signal.

b) Repeat your calculation assuming the use of Nyquist rate sampling.

c) Sketch the timing and synchronization signals needed at the receiver to correctly recover the pulses for each of the twenty-four sources.

Which of the following is an easy way to remember the modified “x” tire rotation? a. nondrive wheels straight, cross the drive wheels b. drive wheels straight, cross the nondrive wheels c. drive wheels crossed, nondrive wheels straight d. drive wheels crossed, nondrive wheels crossed

Steam in a heating system flows through tubes whose outer radius is 2.5 cm and whose walls are maintained at a temperature of 180 °c . circular aluminum alloy 2024-t6 fins ( k= 186 wm. k) of outer radius 3 cm and constant thickness 1 mm are attached to the tube. the space between the fins is 3 mm and thus there are 250 fins per meter of tube length. heat is transferred to the surrounding air at too-25 °c, with a heat transfer coefficient of 40 w/m2. k. manufacturer a claims that this system is rated at 3.5 kw per meter of tube length. if the fins are an integral part of the steam tube, find the heat transfer rate in kw for a 1-m length of tube. is manufacturer a's claim valid? compare the heat transfer rate from 1 meter of tube length if there are no fins.

Air at 27°c and at atmospheric pressure flows over a fat plate at a speed of 2 m/sec. if the plate is maintained at 93°c, calculate the heat transfer for unit wid h of the plate; assuming the length of the plate along the flow of air is 2 metres.