cameroon gce advanced level 2025 communication systems 1
cameroon gce advanced level 2025 communication systems 1
- The trigonometric function S(t) = A(1 + xcosωtcos ωt) representsA Phase modulation
B Amplitude modulation
C Frequency modulation
D Angle modulation
- In a 100% amplitude modulated signal if thetotal power transmitted is Pₜ, then carrier powerwill be
A Pₜ
B Pₜ/2
C Pₜ/3
D 2Pₜ/3
- In television transmission, the type ofmodulation used for video isA VSB
B AM
C FM
D SSB
- An amplitude modulated signal has a carrierfrequency of 10KHz. The upper side band istransmitted at 11KHz. What is the transmission
bandwidth?
A 10KHz
B 1KHz
C 2KHz
D 1KHz
- The maximum transmission efficiency of asinusoidal AM wave isA 100%
B 66.66%
C 33.33%
D 21.68%
- The power output of a transmitter at 30%amplitude modulation is 2.0W. What is thepower content of each side bands?
A 0.045W
B 2W
C 2.09W
D 0.09W
- The standard intermediate frequency used forAM receivers isA 455MHz
B 455KHz
C 455Hz
D 45.5KHz
- The amount of data transmitted for a givenamount of time is called transmissionA power
B frequency
C bandwidth
D noise
- Which of the following is true for frequencymodulation transmission?A Transmission power increases with
increase in modulation level
B Transmission power decreases with
increase in modulation level
C Transmission power decreases with
increase in modulation level
D Transmission power is independent of the
modulation level
- In a frequency modulation system, the maximumallowable deviation is 1000Hz and the audiofrequency is 1KHz. What is the modulation index?
A 1
B 2
C 1000
D 2000
- The amount of frequency deviation in FM signaldepends onA Amplitude of the carrier signal
B Amplitude of the modulating signal
C Frequency of the carrier signal
D Frequency of the modulating signal
- If a carrier wave with frequency 100 MHz ismodulated by a sinusoidal signal of frequency 1KHz,and the maximum frequency deviation being 50
KHz, what is the required transmission bandwidth
according to Carson’s rule?
A 1KHz
B 100MHz
C 50KHz
D 102KHz
- What is the change in the bandwidth of thesignal in FM when the modulating frequencyincreases from 12 KHz to 24KHz?
A 24KHz
B 12KHz
C 48KHz
D 6KHz
- In phase modulated signal, the frequencydeviation isA Constant
B Proportional to frequency
C Proportional to amplitude
D Proportional to both amplitude and
frequency
