Abstract: A deflection circuit includes a deflection correction circuit (Vs) with a controllable active voltage source (Vs) arranged in a loop formed by a deflection coil (Ld), an S-capacitor (Cs), and a flyback capacitor (Cf). The voltage source (Vs) receives a further power supply voltage (Vb2) and a modulating signal (M) to supply a modulating voltage (Vm) varying in response to the modulating signal (M). The active voltage source (Vs) includes a switching element (S2) which is switched on and off with a frequency which is substantially higher than the deflection frequency to to enable waveforms of the modulating voltage (Vm) with a frequency content which is substantially higher than the deflection frequency such that any desired waveform can be generated within the deflection period (Td).

Abstract: The invention relates to a dynamic focusing circuit with an output (1) for supplying a dynamic focusing voltage (Vf) to a focus electrode of a cathode ray tube (CRT). The dynamic focusing voltage (Vf) has, in succession, a falling edge, an almost flat part and a rising edge. A first transistor (T1) has a main current path (c1, e1) coupled between a supply voltage (V+) and the output (1). An arrangement of a secondary winding (Ls) of a transformer (T) and a current determining circuit (12) is coupled between the control input (b1) of the first transistor (T1) and the output (1). The current determining circuit (12) supplies a bias current (Ib). A second transistor (T2) has a control electrode (b2) for receiving an input voltage (Vi) related to a parabolically shaped input waveform (Vin), and a main terminal (c2) coupled to the control input (b1) of the first transistor to withdraw current (Id) from the control input (b1).