The modulator receives the bits from the encryption unit, see GSM 05.01 , and produces an RF signal. The filtering of the Radio Frequency (RF) signal necessary to obtain the spectral purity is not defined, neither are the tolerances associated with the theoretical filter requirements specified. These are contained in GSM 05.05 .
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or non‑specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies.
- A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number.
- For this Release 1999 document, references to GSM documents are for Release 1999 versions (version 8.x.y).
 GSM 01.04: "Digital cellular telecommunication system (Phase 2+); Abbreviations and acronyms".
 GSM 05.01: "Digital cellular telecommunication system (Phase 2+); Physical layer on the radio path General description".
 GSM 05.02: "Digital cellular telecommunication system (Phase 2+); Multiplexing and multiple access on the radio path".
 GSM 05.05: "Digital cellular telecommunication system (Phase 2+); Radio transmission and reception".
Abbreviations used in the present document are listed in GSM 01.04 .