| 摘要 |
The method subjects the product of static collector current (1c) and the emitter resistance (RE) to a predetermined reference voltage (Vref) whose value is equal, within a tolerance, to 13 mV at the temperature of 27 degrees C. The reference voltage is delivered by a generator (GT) of type proportional to the absolute temperature. It is observed that this reference voltage allows for an extremely large value of point of interception of order 3 (IIP3) and provides very good linearity. The electronic device implementing the method comprises an input receiving a signal (+Vin), a coupling capacitor (C), a bipolar transistor (BIP) functioning in class A, the emitter resistor (RE), the reference voltage generator (GT), and an enslave loop (MAS) connected between the emitter and the base of the bipolar transistor for subjecting the product of the collector current and the emitter resistance to the reference voltage. The output impedance of the enslave loop (MAS) is high with respect to the impedance viewed from the base of the transistor, for example 100 times higher. The gain of the enslave loop (MAS) at the frequency of useful signal and at the frequency difference (delta)f between two tones in an intermodulation test is small compared to unity, for example equal to 1/100. The enslave loop (MAS) comprises a differential amplifier, that is a comparator (CMP) whose first input is connected to the emitter of the transistor, the second input to the reference voltage generator, and whose output is connected to the gate of a MOS transistor (T). The MOS transistor (T) is connected between the supply voltage (Vdd) and the base of the bipolar transistor. The device is implemented in the form of an integrated circuit. A distant terminal in a wireless communication system, in particular mobile telephone, incorporates the radio-frequency reception stage comprising the device as claimed.
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