Voltage-controlled oscillator

摘要

It is known that voltage-controlled oscillators are temperature-compensated, as a rule, by means of one or more frequency-determining capacitors having specially selected negative temperature coefficients. The selection of the capacitors is very limited with respect to the number of temperature coefficients for certain capacitance values and this limited number is only obtainable in particular models. According to the invention, the collector terminal of a second transistor arranged in an amplifier stage without load is connected in parallel with respect to direct current with the collector terminal of the oscillator transistor, omitting capacitors having negative temperature coefficients. The second transistor can be an AF transistor, the first transistor has a basic cut-off frequency above 1 GHz with respect to the operating range of some 100 MHz to about 1 GHz.