Method of modulating a data signal with modulation switching between direct and differential modulation and apparatus for modulation
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsAlexander Golitschek, Christian Wengerter, Eiko Seidel
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Abstract
A method and apparatus for modulating a data signal for transmission over a channel of a communication system, wherein a direct modulation scheme is applied to a data signal over a given first signal interval. Subsequently, a control measure is determined for switching the modulation scheme for the data signal from the direct modulation scheme to a differential modulation scheme and/or vice versa, which is applied to the data signal over a given second signal interval.
Claims10
A method of modulating a data signal for transmission over a channel of a communication system, the method comprising:
- determining whether a direct modulation scheme or a differential modulation scheme is being used;
- determining a phase deviation, an amplitude deviation, or both a phase deviation and an amplitude deviation of a received modulation symbol;
- judging whether the modulation scheme in use is to be switched or not based on the determined phase deviation, amplitude deviation, or both phase deviation and amplitude deviation;
- and
- switching from the modulation scheme in use to the other modulation scheme, between the direct modulation scheme and the differential modulation scheme, when it is judged that the modulation scheme in use is to be switched.
An apparatus for modulating a data signal for transmission over a channel of a communication system, the apparatus comprising:
- a first modulator for applying a direct modulation scheme to the data signal;
- a second modulator for applying a differential modulation scheme to the data signal;
- a switching unit that switches the modulator to be used between the first modulator and the second modulator;
- and
- a control unit that operates said switching unit based on a phase deviation value, an amplitude deviation value, or both a phase deviation value and an amplitude deviation value of a received modulation symbol.
Dependencies are inferred from the claim text.