Spectral Estimation Techniques: Correlogram, Blackman–Tukey, Windowed Periodogram, Bartlett, and Welch Methods

1. Which of the following is the primary goal of spectral estimation?

a: To determine the time-domain representation of a signal. Explanation

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b: To estimate the power distribution of a signal over frequency. Explanation

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c: To reduce the noise in a signal. Explanation

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d: To modulate the signal for transmission. Explanation

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2. Which spectral estimation technique uses a window function to reduce spectral leakage?

a: Correlogram Explanation

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b: Blackman-Tukey Explanation

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c: Windowed Periodogram Explanation

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d: Bartlett Explanation

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3. In spectral estimation, what does the periodogram estimate?

a: The time-domain representation of the signal. Explanation

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b: The power spectral density (PSD) of the signal. Explanation

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c: The autocorrelation function of the signal. Explanation

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d: The frequency response of the signal. Explanation

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4. What is the main advantage of using the Bartlett method for spectral estimation?

a: It provides a fast estimation of the frequency components. Explanation

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b: It reduces variance by averaging multiple periodograms from different signal segments. Explanation

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c: It allows for a high resolution of frequency components. Explanation

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d: It requires minimal computation. Explanation

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5. Which technique is specifically designed to address the issue of spectral leakage in spectral estimation?

a: Correlogram Explanation

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b: Blackman-Tukey Explanation

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c: Windowed Periodogram Explanation

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d: All of the above Explanation

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6. Which of the following is true about the Blackman-Tukey spectral estimation method?

a: It is based on the autocorrelation function of the signal. Explanation

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b: It estimates the power spectral density using a smoothing technique. Explanation

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c: It requires the signal to be divided into smaller segments before estimation. Explanation

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d: It is the same as the Windowed Periodogram. Explanation

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7. Which of the following is a disadvantage of the Windowed Periodogram?

a: It can suffer from spectral leakage. Explanation

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b: It results in high variance in the frequency estimate. Explanation

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c: It requires an impractically large amount of data. Explanation

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d: It cannot estimate the power spectral density. Explanation

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8. What does the term 'spectral leakage' refer to in the context of spectral estimation?

a: The loss of signal power in the frequency domain. Explanation

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b: The spreading of energy from one frequency bin to others due to windowing effects. Explanation

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c: The ability to capture higher frequencies that are not present in the signal. Explanation

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d: The phenomenon of noise affecting the power spectral estimate. Explanation

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9. Why is the Welch method considered an improvement over the basic Periodogram?

a: It reduces bias by using a longer data segment. Explanation

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b: It averages multiple overlapping segments to reduce variance. Explanation

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c: It eliminates the need for windowing. Explanation

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d: It increases frequency resolution. Explanation

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10. Which of the following methods is used to estimate the power spectral density of a signal from its autocorrelation function?

a: Correlogram Explanation

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b: Blackman-Tukey Explanation

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c: Windowed Periodogram Explanation

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d: Bartlett Explanation

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