| 摘要 |
<p>1313667 Cathode-ray tube circuits; triangular wave generators LICENTIA PATENT-VERWALTUNGS-GmbH 14 July 1970 [26 July 1969 7 Nov 1969] 34006/70 Headings H3T and H4T In a scanning circuit arrangement for cathoderay tubes in which in order to correct for barrel or pincushion distortion in the line direction, the variably inductive " working " winding of a transductor is connected in parallel with the line scanning coils and the " control " winding supplied with a current of frame repetition frequency, the " working " winding of a second transductor is connected in series with the line scanning coils and its " control " winding is also supplied with a current of frame repetition frequency. With this arrangement the total inductance loading of the line scanning transformer is maintained constant so that variation in fly-back derived EHT, which gives rise to geometric distortions, is prevented. Fig. 1 shows one embodiment in which the " working " winding 8 of the first transductor is connected effectively in parallel with the line scanning coils 4 (supplied from windings 2, 3 on the line scan transformer 1) and the " control " winding 9 connected in series with the frame scanning coils 10, the " working " winding 13 of the second transducter 14 being connected in series with the line scanning coils 4 and its "control" winding 15 supplied with a frame frequency current 15a derived from a winding 16 on the frame scan transformer 12. The current 15a, which has an approximately triangular waveform, is produced by the action of the diodes 21, 22 on the opposite polarity sawtooth voltages 18, 19 a further diode 24 being utilized to clip the peaks 25. Other circuit arrangements for producing the current for the " control " winding 15 are shown in Figs. 2, 3 and 4. In a second embodiment the two " control " windings 9 and 15 are connected in series and the circuit for producing the current 15a includes means for adjusting the magnitude thereof (Fig. 5, not shown). In a modification of the latter circuit the voltage derived from the winding on the frame scan transformer (similar to winding 17, Fig. 1) is pre-distorted so that the triangular current 15a flowing in the " control " winding 15 retains its symmetry despite variation with frequency of the control windings. (Fig. 6, not shown.)</p> |
