High-frequency signal injection device, adapted to operate a high-frequency device, in the form of a high-frequency lamp or high-frequency spark plug, wherein the high-frequency signal injection device comprises: - an oscillator for generating a high-frequency signal which is supplied to the high-frequency device for its operation; - means adapted to generate a voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device on the basis of the high-frequency signal generated by the oscillator and supplied to the high-frequency device and a signal reflected from the high-frequency device; and - a device for generating a regulating signal (U A) for adjusting the output frequency of the oscillator based on the voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device, characterized in that the device comprises a filter device and an amplitude discriminator, wherein the amplitude discriminator comprises a comparator, a voltage value generating device and a logic unit, wherein the logic unit comprises at least one logic gate (61, 63, 59); wherein a fixed voltage value is generated by the voltage value generating device, wherein the voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device and the fixed voltage value are supplied to the comparator, whereby the proportional voltage signal (U prop) and the fixed voltage value are compared and a first condition is generated, wherein the amplitude discriminator is adapted to generate a second condition based on the voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device, wherein the first condition and the second condition are supplied to the at least one logic gate (59, 61, 63) of the logic unit, wherein the amplitude discriminator is further adapted to generate and output a digital or clocked output voltage (U D) to the filter device based on the first condition, the second condition and a truth table on which the at least one logic gate (61, 63, 59) is based, wherein the filter device is designed to smooth the digital or clocked output voltage (U D) in such a way that an analog output signal (U A) is generated which is output to the oscillator as a regulating signal for adjusting the output frequency. - an oscillator for generating a high-frequency signal which is supplied to the high-frequency device for its operation; - means adapted to generate a voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device on the basis of the high-frequency signal generated by the oscillator and supplied to the high-frequency device and a signal reflected from the high-frequency device; and - a device for generating a regulating signal (U A) for adjusting the output frequency of the oscillator based on the voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device, wherein the amplitude discriminator comprises a comparator, a voltage value generating device and a logic unit, wherein the logic unit comprises at least one logic gate (61, 63, 59); wherein a fixed voltage value is generated by the voltage value generating device, wherein the voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device and the fixed voltage value are supplied to the comparator, whereby the proportional voltage signal (U prop) and the fixed voltage value are compared and a first condition is generated, wherein the amplitude discriminator is adapted to generate a second condition based on the voltage signal (U prop) proportional to the degree of adaptation of the high-frequency device, wherein the first condition and the second condition are supplied to the at least one logic gate (59, 61, 63) of the logic unit, wherein the amplitude discriminator is further adapted to generate and output a digital or clocked output voltage (U D) to the filter device based on the first condition, the second condition and a truth table on which the at least one logic gate (61, 63, 59) is based, wherein the filter device is designed to smooth the digital or clocked output voltage (U D) in such a way that an analog output signal (U A) is generated which is output to the oscillator as a regulating signal for adjusting the output frequency.