Philips Colour Television Service Manual page 90

EN 90 9. DPTV585 AA
9.3.15 HOP Sharpness Control
Figure 9-22 HOP sharpness control
The Sharpness controls for the YUV/RGB signals are located
on the HOP panel. Since all three circuits are basically the
same, only the Blue one will be discussed.
The Blue signal is fed to pin 1 of 7410. It is also fed to a Low
Pass filter consisting of 5411 and 5410. This path is amplified
by transistor 7411. The Low Pass filter blocks the higher
frequencies as well as shifting the phase of the signal. The
output of the Low Pass filter is also fed to pin 4 of 7410. The
mixing of these two-phase shifted signals only allows the High
frequency component to be amplified and output on pin 12. The
gain of the High frequency component is controlled by the
Sharpness voltage, which is applied to Pins 8 and 10. The two
signals are combined at pin 12 of the IC. If the input was a Blue
Circuit Descriptions, List of Abbreviations, and IC Data Sheets
Figure 9-21 HOP signal processing
9.3.16 HOP Tint Control
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signal, it is amplified by 7412 and buffered by 7413. If the input
was a U signal, it is buffered by 7414.
Figure 9-23 HOP tint control
IC 7510 amplifies the U signal while 7520 amplifies the V
signal. The Tint control voltage changes the balance between
the U and V signals to change, causing the tint of the picture to
change.
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