meters above the horizontal plane of the approach end of the runway threshold for Facility Performance Category II-ILS and Category III-ILS) as shown in the following diagrams.
Remarks:
I. The rated coverage shall be the shaded portion indicated by the oblique lines.
II. Point “R“”" is the paint of intersection of the glide path and the runway.
III. θ is the glide path with respect to the horizontal.
(｡ｪ)The frequency tolerances of the 90 Hz and 150 Hz tones shall not exceed 2.5 percent for Facility Performance Category I-ILS glide slope equipment, 1.5 percent for Facility Performance Category Il-ILS glide slope equipment, and 1.0 percent for Facility Performance Category III-ILS glide slope equipment.
(ｪ)The phase characteristics of the 90 Hz and 150 Hz modulated waves shall be as follows on the half glide path center (the sector portion at which DDM is not more than 0.0875 at the vertical plane of the glide path).
I. Each voltage of the 90 Hz and 150 Hz modulated waves shall be zero in the same direction in every half-cycle of the combined 90 Hz and 150 Hz modulated waves for a period not exceeding 370 microseconds for Facility Performance Category I-ILS, the Facility Performance Category II-ILS and 185 microseconds for Facility Performance Category III-ILS.
II. With dual-frequency glide slope, each voltage of the 50 Hz modulated waves of the two carriers shall be zero in the same direction for a period
not exceeding 370 microseconds for Facility Performance Category I-ILS and Category II-ILS glide slope equipment and 185 microseconds for Facility Performance Category III-ILS glide slope equipment.
(ｪ｡)The percentage modulation of the radio frequency carrier for each of the 90 Hz and 150 Hz modulated waves shall be 40 percent on the glide path and the tolerance shall not exceed 2.5 percent.
(ｪ｢)The total harmonic content of the 90 Hz and 150 Hz tones shall not exceed 10 percent and the second harmonic contents of the 90 Hz modulated wave shall not exceed 10 percent.
