Nokia-mobira Oy

Erkki J Kuisma

A circuit arrangement allows either analog (ANAL) modulation or (DIG) digital modulation to be selected by means of couplers (K1, K2) for transmission over a radio channel. The analog or digital signals are applied to I,Q generators to form I, Q wave shapes (I.sub.A, Q.sub.A or I.sub.D, Q.sub.D), which modulate a possible intermediate frequency in a stage (3) and upon summation, modulate a transmission frequency in a stage (4).

Combined analog/digital frequency modulator

A control voltage generator in a transmitter arrangement for, e.g., QAM signals comprising a class C output amplifier (AMP). The control voltage generator (CVG) comprises a memory with a look up table (ROM), whereby the I,Q-signals (I,Q) of the modulating signal (DM) address a cell in the look-up table (ROM), the information of which is used as a control signal (CS) to control the amplifier output level (RF). The information is modified to compensate for temperature variations and other non-linearities.

Control voltage generator in a transmitter arrangement for digitally

A radio transmitter arrangement for e.g. QAM signals comprising a class C output transistor amplifier (AMP). The control voltage generator (CVG) comprises a memory, whereby the I,Q-signals (I,Q) of the modulating signal (DM) address the control voltage generator (GEN), the information of which is used as a control signal (CS) acting as the collector voltage to control the amplifier output level (RF). The information can be modified to compensate for temperature variations and other non-linearities.

Transmitter arrangement for digitally modulated signals

In a circuit arrangement for the generation of I,Q waveforms, an incoming analog signal controls a voltage-controlled oscillator (1), whose output signal (U1) is frequency-modulated. This signal (U1) is mixed with unmodulated signals by using mixers that are switches (6,7). The signals controlling the switches are either modulated or oscillator-generated rectangular waves. The circuit arrangement can be implemented as an integrated circuit.

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Salo, Finland

Erkki J Kuisma