TUNABLE RESONANCE AMPLIFIER

摘要

Tunable resonance amplifier comprising a non-regenerative DC negative feedback loop having a controlled loop gain, which loop incorporates first and second first-order low-pass RC filters (R1C1, R2C2), and having a signal path arranged from an input to an ouput and a feedback path arranged from the output to the input. In order to realise a substantially equal selective amplification over a comparatively large tuning control range, the signal path incorporates one of the two said RC filters and the feedback path incorporates the other RC filter together with the controlled loop gain, or the signal path incorporates the two said RC filters together with one part of the controlled loop gain and the feedback path incorporates the other part of the controlled loop gain. To realise a reduction in the required power supply voltage and hence a decrease of the power dissipation of a frequency synthesis circuit, a tunable resonance amplifier is arranged between the voltage-controlled oscillator and the frequency divider circuit, and the loop filter is coupled to a tuning control input of the tunable resonance amplifier for simultaneously tuning the voltage-controlled oscillator and the tunable resonance amplifier.