# Bandpass Modulation Technique MCQ [Free PDF] – Objective Question Answer for Bandpass Modulation Technique Quiz

1. Wavelength and antenna size are related as

A. λ/2
B. λ/4
C. 2λ
D. 4λ

The transmission of the Em field in space is done with the help of antennas. Antenna size depends on the wavelength. The length of the antenna is equal to λ/4.

2. The detection method where the carrier’s phase is given importance is called as

A. Coherent detection
B. Non-coherent detection
C. Coherent detection & Non-coherent detection
D. None of the mentioned

When the receiver uses the carrier’s phase as a major factor for detection then it is called coherent detection and when the carrier is not given the importance it is called non-coherent detection.

3. The coherent modulation techniques are

A. PSK
B. FSK
D. All of the mentioned

Some examples of coherent modulation techniques are phase-shift keying, amplitude shift keying, frequency-shift keying and continuous phase modulation.

4. The real part of a sinusoid carrier wave is called as

A. Inphase
D. None of the mentioned

The two main parts of the sinusoid carrier wave – the real part is called in-phase and the imaginary part is called as quadrature.

5. Antipodal signal sets are those vectors that can be illustrated as

A. Two 180 opposing vector
B. Two 90 opposing vector
C. Two 360 opposing vector
D. None of the mentioned

In BPSK the two vectors, the signal set can be illustrated as two 180 opposing vectors which are called antipodal signal sets.

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6. The FSK signal which has a gentle shift from one frequency level to another is called as

A. Differential PSK
B. Continuous PSK
C. Differential & Continuous PSK
D. None of the mentioned

In general FSK the signal change from one frequency to another will be abrupt but in continuous FSK the signal change from one frequency to another will be gentle and gradual.

7. Which modulation scheme is also called as on-off keying method?

B. FSK
C. PSK
D. GMSK

In the ASK modulation scheme, the signal attains either maximum amplitude or zero point. Thus it is also called on-off keying.

8. In amplitude phase keying each phase vector is separated by

A. 90
B. 0
C. 45
D. 180

The combination of ASK and PSK is called APK. In APK each vector is separated by 45.

9. The term heterodyning refers to

A. Frequency conversion
B. Frequency mixing
C. Frequency conversion & mixing
D. None of the mentioned

The term heterodyning means frequency conversion and frequency mixing that yields a spectral shift in the signal.

10. The transformation of the waveform into a single point in signal space is called as

A. Vector point
B. Predetection point
C. Preamplification point
D. Transformation point

The first step of the detection process is to reduce the waveform into a single or group of random variables. This first step in the transformation of the waveform into a point in signal space. This point is called a pre-detection point.

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