Broadband multicarrier modulator and corresponding programming method
AssigneeAlcatel
InventorLuc Dartois
Life of this patent
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Abstract
In a broadband multicarrier modulator, all processing within a modulator is replaced by a pre-computed table so that a modulated signal can be produced as a function of the modulating signal merely by reading the table. The carrier frequency of the modulator is even programmable. The size of the pre-computed table is reduced by using an automation. With this automation the address for reading the table at a given time depends on preceding values of the modulating signal. By reading the table on a time sharing basis it is even possible, with a single modulator, to perform the work of several modulators. A multicarrier modulator is then easily implemented.
Claims12
A method of programming the automaton of a modulator, in particular for a mobile telephone network with base transceiver stations and mobile telephones, said modulator including a signal input, a modulator circuit in which a signal at said input modulates a carrier, and a transmit circuit for broadcasting said carrier by radio, said modulator circuit including:
- an automaton for producing an arbitrary encoded state for bits of said signal at said input and a preceding arbitrary encoded state of said automaton, and
- a pre-computed table for transforming said arbitrary encoded state into an instantaneous signal that is fed into said transmit circuit,
- in which programming method:
- the evolution of an ideal modulator for a given type of modulation and for different configurations of bits of said input signal is simulated and trajectories are produced as output signals of said modulator,
- modulation state references and trajectory references are allocated arbitrarily to said configurations,
- an automaton is constructed by allocating said modulation state and trajectory references in one table to an address of a record of said automaton and assigning said trajectories in another table to an address corresponding to said trajectory references, and
- an arbitrary state corresponds to a preceding configuration of said input signal modified by the value of the bit of said input signal.
Dependencies are inferred from the claim text.