Modulator apparatus operating at low supply voltage, and corresponding method of modulation

A method of modulation operating at a low supply voltage, comprising:

• receiving an input-voltage signal in base band and supplying an output-voltage signal at a modulation frequency under control of a signal generated by a local oscillator;
• carrying out a voltage-to-current conversion of said input-voltage signal and an operation of mirroring of a current obtained;
• carrying out a frequency conversion via a Gilbert-cell stage under the control of said signal generated by said local oscillator;
• carrying out a current-to-voltage conversion and supplying the output-voltage signal;
• and
• applying a differential feedback for reproducing in a proportional way said input-voltage signal on a differential load that controls said voltage-to-current conversion.

A transconductor circuit comprising:

• a current mirror circuit configured to generate a differential current signal;
• a first differential amplifier operable to receive a first voltage signal and generate an output signal to control the current mirror circuit;
• a voltage-to-current conversion circuit to receive a second voltage signal proportional to the first voltage signal and convert the second voltage signal to a current signal;
• and
• a second differential amplifier operable to control the voltage-to-current conversion circuit.