CNS–ST 1.1: INTRO TO COMMS, NOISE AND dB MEASURMENTS1.The theory of radio waves was originated by:Ans. Maxwell *2.The first person who sent the first radio signal across the Atlantic ocean:Ans. Marconi *3.The transmission of radio waves was first done by:Ans. Hertz *4.When two or more signals share a common channel, it is called:Ans. Multiplexing *5.“Man-made” noise can come from:Ans. equipment that sparks *6.Thermal noise is generated in: Ans. transistors and diodes, copper wire, and resistors *7.Shot noise is generated in:Ans. transistors and diodes *8.The power density of “flicker” noise is:Ans. greater at low frequencies *9.So called “1/f” noise is also called:Ans. pink noise *10.“Pink” noise has:Ans. equal power per octave *11.Noise figure is a measure of:Ans. how much noise an amplifier adds to a signal *12.Resistor that generates the lowest thermal noise:Ans. wire-wound *13.Resistor with typical voltage range of Ans. metal film*14.Reference for noise temperature in ˚C:Ans. 17 *15.Standard test tone connected on audio equipment?16.Reference standard test tone normally used is indicated in:Ans. dBm *17.Power lost in device, due by the path of energy flow.Ans. insertion loss *18.The noise generated with semiconductor devices.Ans. shot noise *19.Bandwidth is approximately _____ the highest baseband frequency.Ans. 2 times * 20.Flicker noise in radio communications is also known as.Ans. pink noise *21.What determines the BW of a transmitted signal?22.What formula is used to calculate the overall noise performance of the receiver or of multiple stages if RF amplification?23.If the bandwidth is doubled, considering all other parameters unchanged except the normal thermal noise only. The S/N will be___Ans. decreased by 3 dB *24.Noise at the receiver is in terms of:Ans. µV *25.Reference tone level for µBa:Ans. – 85 dBm *26.Reference tone level for dBrn:Ans. -90 dBm *27.Reference tone level for F1A:Ans. -85 dBm *28.Reliable measurement for comparing amplifier noise characteristics:Ans. noise factor *NOISE PROBLEMS29.A receiver has noise power bandwidth of 10 kHz. A resistor that matches the receiver input impedance is connected across its antenna terminals. What is the noise power contributed by that resistor in the receiver bandwidth if the resistor has a temperature of 27 degrees Celsius?Ans. 30.A 300 ohm resistor is connected across the 300 ohm antenna input of the television receiver. The bandwidth of the receiver is 6 MHz, and the resistor is at room temperature. Find the noise power and noise voltageapplied to the receiver input.Ans. 24.2 fW, 2.7 uV.