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a radar systemuses pulses of duration d tomodulate the amplitude of a radio carrierwave the system can distinguish between targets spaced apart by a
suppose that a video signal having w 5 mhz is transmitted via fm with f 20 mhz for 1100 le bfc le 110 determine the bounds on the carrier frequency
the operating frequency range of a superheterodyne fmreceiver is 88-108mhz the if and lo frequencies are so chosen that fif ltfloifthe image
let a message signal mt have a bandwidth of 10 khz and a peak magnitude of 1 v estimate the bandwidth by using carsons rule of the signalut obtained
q let m1t and m2t be two message signals and let u1t and u2t be the corresponding modulated versionsa when the combined message signal m1t m2t dsb
an angle-modulated signal has the form ut 100 cos 2pifct4 sin 2pifmt where fc 10mhz and fm 1 khz determine the modulation indexbetaf or betap and
let the message signal mt alpha cos 2pifmt be used to either frequency-modulate or phase- modulate the carrier ac cos2pifct find the modulated
let the modulating signal mt be a sinusoid of the form mt cos 2pifmt fm ltlt fc and let the carrier signal be cos2pifct phica determine the
the normalized signal xnt has a bandwidth of 10 khz and its power content is 05 w while the carrier ac cos 2pifct has a power content of 200w find
q for dsb and conventional am obtain expressions for the in-phase and quadrature components xdt and xqt and envelope and phase vt and
if a television station operates on uhf channel 20 band 506-512 mhz determine the stations visual-carrier
q show that the image frequency for an fm station does not fall in the range of 881-1079 mhz regardless of the choice of high- or low-side local
q a voice message with wf 2pi3times103 rads and wrms 2pi1 times 103 rads is transmitted over an fm broadcast system with standard emphasis and
q an fm stations modulator has a sensitivity kfm 5pi times 104 radsmiddotv a receiver uses a discriminator that has a gain constant of 10-5 pi
q a commercial fmstation broadcasts a signal with 180-khz bandwidth when ftmax 2 v find kfm for the modulator if the spectral extent of f t is 30
the signal mt whose frequency spectrum mf is to be transmitted from one station to another let the signal be nor- malized ie -1 le mt le 1 find the
q if the output signal fromanammodulator is given by ut 5 cos 1800 pit 20 cos 2000 pit 5 cos 2200 pit determinea the modulating signal mt and
although the low side is not as good a choice as the high-side local oscillator frequency let an am broadcast receiver be designed with a low-side
at the transmitter in a standard am system pf 50 w in the receiver s0n0am 250 when si ni am 3000 find the transmitters unmodulated carrier power
q in an am transmitter that transmits a total power of 1 kw the unmodulated carrier power is 850 w compute the required value of si ni am at a
q let at 1 maxt and xt cos 2pifmt fm ltlt fc and xct at cos 2pifct a with ma 1 sketch one full period of the am wave and draw the envelope by
q find the number of possible station frequencies in the am broadcast system in the united
q a an amplier with f0 3 or 477 db f0 4 ghz and bn 14 mhz is used with an antenna forwhich ta 200k the connecting path loss is 145 or 161 db at a
q an antenna with an effective noise temperature of 130 k couples through a waveguide that has a loss of 08 db to a receiver find the effective noise
q determine the effective input noise temperature of a long piece of waveguide that connects an antenna to a receiver with a loss of 34 db at 12 ghz