Avoidance of discontinuities when switching between modulation schemes

US7719376B2 · kind B2 · utility

Assignee

• ST-ERICSSON SA · CH

Inventors

• Alexander Lampe · Leipzig, DE
• Rainer Dietsch · Heroldsberg, DE

Key dates

• Filing date: Nov 24, 2004
• Grant date: May 18, 2010
• Expiry date: Aug 22, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L27/0008
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

Modulator system (1) comprising modulators (2, 3, 4) for modulating input signals (A) according to different modulation schemes (8PSK, GMSK) cause discontinuities in the output signals (F) when switching between the schemes. By providing the modulator systems (1) with compensators (13, 22-26) for compensating amplitudes/phases of the output signals (F) of the modulator system (1) for discontinuities, these discontinuities resulting from modulation scheme changes are reduced to a large extent. This may be done before/after the pulse shapers (11, 21). The compensators (13, 22-26) comprise multipliers for multiplying pulse shaped modulated signals with complex valued waveforms (E), or for multiplying modulated signals with waveforms (S, T), or for multiplying complex valued signals (B, C, D) with complex valued phase offsets (X, Y, Z), which complex valued signals (B, C, D) are to be multiplied with mapped input signals. As a result, the output signals (F) and/or power amplifiers (33) situated after the modulator system (1) no longer need to be ramped down.