Additional errata for the DSP 1st textbook.
p56, solid line in top of Fig. 3.6 should have amplitude 1, not 7!
p120
The notation y[n] = T{x[n]} is terribly dangerous, since y[n] might
depend on all values of x[.], not just x[n].
More precise notation would be y = T{x} or y[n] = (T{x})[n].
p148 (Ch 5, example 5.3), table.
It should have h_2[0]h_1[n-0] instead of h_1[0]h_2[n-0], etc for the 3 lines,
(h_1 and h_2 are reversed).