Virtual Labs

Pulse Amplitude Modulation (PAM), Pulse Width Modulation (PWM), Pulse Position Modulation(PPM), Pulse Coded Modulation & their Demodulation

1. What is the primary characteristic of a Pulse Amplitude Modulation (PAM) signal?

a: The amplitude of the pulses varies according to the amplitude of the modulating signal. Explanation

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b: The width of the pulses varies according to the amplitude of the modulating signal. Explanation

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c: The position of the pulses varies according to the amplitude of the modulating signal. Explanation

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d: The frequency of the pulses varies according to the amplitude of the modulating signal. Explanation

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2. In Pulse Width Modulation (PWM), what aspect of the pulse varies?

a: Amplitude Explanation

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b: Width Explanation

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c: Position Explanation

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d: Frequency Explanation

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3. Which of the following is true for Pulse Position Modulation (PPM)?

a: The amplitude of the pulses is varied. Explanation

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b: The position of the pulses is varied. Explanation

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c: The width of the pulses is varied. Explanation

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d: The frequency of the pulses is varied. Explanation

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4. In Pulse Code Modulation (PCM), which of the following steps occurs first?

a: Quantization Explanation

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b: Sampling Explanation

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c: Encoding Explanation

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d: Modulation Explanation

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5. What is a major advantage of Pulse Amplitude Modulation (PAM) over analog amplitude modulation?

a: PAM signals require less bandwidth. Explanation

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b: PAM signals are more resistant to noise. Explanation

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c: PAM signals are easier to generate. Explanation

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d: PAM signals have higher fidelity. Explanation

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6. In PWM, how does an increase in the amplitude of the modulating signal affect the pulse width?

a: It decreases the pulse width. Explanation

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b: It increases the pulse width. Explanation

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c: It has no effect on the pulse width. Explanation

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d: It increases the pulse amplitude. Explanation

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7. Which type of pulse modulation is least affected by timing jitter in the transmission system?

a: PAM Explanation

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b: PWM Explanation

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c: PPM Explanation

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d: PCM Explanation

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8. What does the quantization step in Pulse Code Modulation (PCM) achieve?

a: It converts the analog signal to a digital bit stream. Explanation

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b: It samples the analog signal at regular intervals. Explanation

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c: It maps the sampled values to the nearest available level. Explanation

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d: It modulates the digital signal for transmission. Explanation

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9. How is the resolution of a Pulse Code Modulation (PCM) signal determined?

a: By the sampling frequency. Explanation

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b: By the number of quantization levels. Explanation

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c: By the width of the pulses. Explanation

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d: By the bit rate of the encoded signal. Explanation

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10. In Pulse Position Modulation (PPM), how does a higher frequency modulating signal affect the pulses?

a: The pulses move closer together. Explanation

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b: The pulses move further apart. Explanation

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c: The pulse width decreases. Explanation

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d: The pulse amplitude increases. Explanation

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