Electrically controllable oscillator circuit and electrically controllable filter arrangement comprising said circuit.

摘要

An electrically controllable oscillator circuit (30) comprises two balanced transconductance circuits (G1, G2), each comprising transistor pairs arranged as inverters (Inv1-4) and as resistors (Inv5-6). To control the oscillation frequency (f) and the quality factor (Q) of the oscillator circuit (30) by means of a single control signal there is provided a combined control circuit (Inv7, Dif, IM1, IM2). By means of current mirror circuits (IM1, IM2) and a differential pair (Dif) the control signal for adjusting the quality factor (Q) is derived from a resistor-connected further transistor pair (Inv7) connected to the control signal for adjusting the frequency (f). For adjusting the quality factor of an electrically controllable filter arrangement comprising similar transconductance circuits (G3-9) by means of the control signal generated by the control circuit (Inv7, Dif, IM1, IM2) there is provided a buffer circuit (B) and a low-pass circuit (C3). <IMAGE>