A certain communication channel is characterized by a 60 dB attenuation and additive white noise with the power spectral density of N/2=0.5 * 1014 W/Hz. The bandwidth of the message signal is 1 MHz, and its normalized power is W. If we require that the SNR after demodulation be 30 dB, find the necessary transmitter power in each of the following cases: A) Upper single-sideband (USSB) modulation.
B) DSB-SC modulation.
C) Conventional AM with a modulation index of 0.5.

Determine the time of the day and month of the year at which the peak sensible cooling load occurs for a top floor, north-eastern corner room of an office building in durban for the following conditions: floor area: 8 x 8 x 3 m east and north walls: 115 mm face brick (outside), 20 mm air space, 115 mm ordinary brick (inside) with 15 mm plaster roof construction: suspended plasterboard ceiling, 450 mm air space, 150 mm concrete, 75mm screed, waterproofing no heat transfer across other surfaces window area 3x 1,5 m high in north wall only. ordinary glass with venetian blinds. lights and occupants : from 07: 00 to 18: 00 average light density: 25 w/m2 number of occupants : 5 seated, light office work room temperature 24°c