The theory of radio waves was originated by:

Who invented FM:

Reginald FessendenPhilo Farnsworth Edwin ArmstrongHeinrich Hertz

The FM modulation index:a. increases with both deviation and modulation frequencyb. increases with deviation and decreases with modulation frequencyc. decreases with deviation and increases with modulation frequencyd. is equal to twice the deviationOne way to derive FM from PM is:a. integrate the modulating signal before applying to the PM oscillatorb. integrate the signal out of the PM oscillatorc. differentiate the modulating signal before applying to the PM oscillatord. differentiate the signal out of the PM oscillatorThe bandwidth of an FM signal is considered to be limited because:a. there can only be a finite number of sidebandsb. it is equal to the frequency deviationc. it is band-limited at the receiverd. the power in the outer sidebands is negligibleMathematically, the calculation of FM bandwidth requires the use of:ordinary trigonometry and algebraBessel functions Taylor seriesFractalsFM bandwidth can be approximated by:Armstrong's Rule Bessel's Rule Carson's Ruled. None of the aboveNBFM stands for:National Broadcast FM Near Band FMb. Non-Broadcast FM d. Narrowband FMWhen FM reception deteriorates abruptly due to noise, it is called:the capture effect the threshold effect the noise effectd. the limit effectAn FM receiver switching suddenly between two stations on nearby frequencies is called:a. the capture effectb. the threshold effect c. the "two-station" effect d. none of the abovePre-emphasis is used to:a. increase the signal to noise ratio for higher audio frequenciesb. increase the signal to noise ratio for lower audio frequenciesc. increase the signal to noise ratio for all audio frequenciesd. allow stereo audio to be carried by FM stationsPre/Deemphasis Response500 Hz 2120 Hz 15KHz-17dB17dB+3dB-3dBpreemphasisdeemphasisDeemphasis circuitIs between the detectorAnd the audio amplifierA pre-emphasis of 75 us refers to:a. the time it takes for the circuit to workb. the "dead time" before de-emphasis occursc. the time delay between the L and R channelsd. the time-constant of the filter circuits usedFM stereo:a. uses DSBSC AM modulationb. is implemented using an SCA signal c. has a higher S/N than mono FM d. is not compatible with mono FMAn SCA signal:a. can use amplitude modulationb. can use FM modulation c. is monaural d. all of the aboveThe modulation index of an FM signal can be determined readily:a. using measurements at points where J0 equals oneb. using measurements at points where J0 equals zeroc. using measurements at points where the deviation equals zerod. only by using Bessel functionsFM and PM are two forms of ________ modulation.angle

PM is extensively used in _______ communication.data

Compared to AM, the signal-to-noise ratio of FM is usually ___________.better

FM transmitters can use Class _________ amplifiers since amplitude linearity is notimportant.C