The IBOC Handbook

Glossary

Absolute Layer 1 Frame Number (ALFN) – A sequential number assigned to every Layer 1 frame. The start time of ALFN 0 was 00:00:00 Universal Coordinated Time (UTC) on January 6, 1980. Each subsequent ALFN is incremented by one from the previous ALFN. The present time can be calculated by multiplying the next frame's ALFN times the frame duration, T_f, and adding the total to the start time of ALFN 0.

All-Digital Waveform (or Signal) – The IBOC waveform intended to be broadcast without an accompanying host analog signal. In the absence of an analog signal for fast audio acquisition upon tune-in, the All-Digital signal contains a fast-acquisition digital audio stream that is reinforced when the more robust copy of the digital audio stream ...