UNIT IV REVISION

Coherence time refers to ____________

• Time required attaining a call with the busy base station

• Time required for synchronization between the transmitter and the receiver

• Minimum time for change in magnitude and phase of the channel

• None of the mentioned

Doppler spread refers to _________

• Signal fading due to Doppler shift in the channel

• Temporary failure of message transfer

• Large coherence time of the channel as compared to the delay constraints

• All of the mentioned

Which of the following is not used to improve received signal quality over small scale times and distance?

• Modulation

• Equalization

• Diversity

• Channel coding

Equalization is used to compensate __________

• Peak signal to noise ratio

• Intersymbol interference

• Channel fading

• Noises present in the signal

Training and tracking are the operating modes of _________

• Diversity techniques

• Channel coding techniques

• Equalization techniques

• Demodulation techniques

An equalizer is said to be converged when it is properly _______

• Trained

• Tracked

• Installed

• Used

Time for convergence of an equalizer is not a function of _______

• Equalizer algorithm

• Equalizer structure

• Time rate of change of multipath radio channel

• Transmitter characteristics

Equalizer is usually implemented in __________

• Transmitter

• Baseband or at IF in a receiver

• Radio channel

• Modulator stage

Equalizer is ________ of the channel.

• Opposite

• Same characteristics

• Inverse filter

• Add on

______ controls the adaptive algorithm in an equalizer.

• Error signal

• Transmitted signal

• Received signal

• Channel impulse response