# Intuitive Guide to Fourier Analysis .. Errata sheet

### Errata List for Intuitive Gide to Fourier Analysis and Spectral Estimation, First Edition

Feel embarrassed that after reading the stuff twenty times, one seems to not notice even the most glaring errors. Well, thats my excuse any way!

Your indulgence required until the next edition.

Here I have listed all the errors and typos that have already been corrected in the Kindle version but remain in the First edition of the book. Please add you discoveries below in the comment section. .

These apply only to the printed book. They have already been corrected in the electronic version.

(Equations are given in Latex)

Chapter 1: page 21, below Eq. 1.16, the last line should say {Now the whole expression uses only the cosine waves and the index, $k$ spans not just from $0$ to $\infty$, but from $-\infty$ to $+\infty$.}. – By Robert Lingenfelter

Chapter 2:  Eq. 2.11 thru Eq. 2.22 should have a subscript 0 to the frequency, $\omega_0$ instead of $\omega$ alone.  This subscript makes it clear that $\omega$ is not a variable but is a constant, the starting or the fundamental frequency.
Chapter 2: – Eq. 2.21 and in Eq. 2.22 the sign of the exponential is reversed. The first one should be minus and second, a plus.
Chapter 2: – Eq. 2.24 is missing the term $t$, should be $e^{\j k \omega \underline{t}}$.
Page 59: The duty cycle term is $\tau{/T$ and not $\tau$ alone.
Page 57: Example 2.9, the signal should be \newline$x(t) = 3+ 6\cos(4\pi t+2)+\underline{4}\j\sin(4\pi t+3)- 3\j \sin(10\pi t+1.5)$\newline Note the underlined quantity $4$ for the third term, $\j \sin(4\pi t+3)$.
Page 58: The calculated value of the coefficient  $e^{-\j 4\pi t}$ should be 2.552. The corresponding Fig. 2.14 has been changed. \item Page 68: Example 2.15 The correct answer is -0.142 instead of 0.142.Page 59: The duty cycle term is $\tau{/T$ and not $\tau$ alone.
Page 58: The calculated value of the coefficient  $e^{-\j 4\pi t}$ should be 2.552. The corresponding Fig. 2.14 has been changed.

Page 68, Example 2.15 The correct answer is -0.142 instead of 0.142.

Page 74: Figure 3.3 (a), the y axis has been moved to the center of the shape to be consistent with figures (b) and (c).
Page 75: Eq. 3.8, added subscript s to Time T.
Page 83:  Last line, the equation number should be (3.17) instead of (3.19).
Page 86: First paragraph, last line, should be “with only 1 Hz” and not 2 Hz.
Page 92: Third paragraph, third line, should be $11 \pi /5$ and not $12 \pi /5$
Page 97: Eq. (3.37) and eq. (3.38) are missing the coefficient $1/N_0$ from the front of the RHS.
Page 102: The correct values for the coefficients are: 1.5,  .612, 0.5 and 0.612, as shown in the figure 3.25.
Page 103: Correct coefficients are: 0.75, 0.56, 0.25 and 0.56.
Page 104: Added subscript 0 to N to clarify that this is the fundamental period.Chapter 2 – Eq. 2.11 thru Eq. 2.22 should have a subscript 0 to the frequency, $\omega_0$ instead of $\omega$ alone.  This subscript makes it clear that $\omega$ is not a variable but is a constant, the starting or the fundamental frequency.
Chapter 2 – Eq. 2.21 and in Eq. 2.22 the sign of the exponential is reversed. The first one should be minus and second, a plus.
Chapter 2 – Eq. 2.24 is missing the term $t$, should be $e^{\j k \omega \underline{t}}$.

###### 2 comments on “Intuitive Guide to Fourier Analysis .. Errata sheet”
1. Chandru Aswani says:

In Chapter 2, Eq 2.3, I noticed that the right-hand side contains a ‘j’ in the denominator. Is this a typo?

Many thanks for this lucid book!

• Charan L. says:

Do believe you are correct. the “j” on the numerator should not be there. Another item to be added to the erratta. Thanks for pointing it out. How do you like the book otherwise?
Charan Langton Please send me your address, I will send you a free copy of the book.