Panasonic EURO 4 Chassis Technical Manual page 19

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9.3. East/West Correction

To compensate for the pincushion distortion in

east/west direction in the case of 110

horizontal deflection current must be increased at

vertical centre in relation to vertical start and vertical

end.

This correction is achieved by the horizontal

deflection current being influenced with a vertical

frequency parabola in the east/west diode modulator

D551, D552.

Output from the VDP IC601, pin 32 a parabola

waveform of 1v pp occurs which is passed via R847

to buffer transistor

•

sets, the

of the East / West IC. IC701.

Here the parabola waveform is fed to a comparator,

where the parabola waveform is compared with the

horizontal flyback pulse, from the output of the

comparator the E/W drive signal is output via pin 5

and fed to the diode modulator via R702 and the

E/W charging coil L701.

This E/W signal is then superimposed onto the

deflection current with the aid of the diode

modulator, thus performing E/W correction.

3DQDVRQLF

Q701

before being input via pin 7

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