Daewoo DTL-2950K Service Manual

Also see for DTL-2950: Manual instruction Instruction manual

CP-650 Service ManualDTV R&D Europe 38available on one of the other CVBS inputs.In this condition the connections between the vision IFamplifier and the synchronisation circuit can be switched on and off by means of the VDX bit.The VDXEN bit must be set to “1” for this mode.The vertical synchronisation is realised by means of a divider circuit.5.2.7 Horizontal and vertical driveThe horizontal drive is switched on and off via the soft start/stop procedure. The soft startfunction is realised by means of variation of the TON of the horizontal drive pulses. During thesoft-stop period the horizontal output frequency is doubled resulting in a reduction of the EHT sothat the picture tube capacitance can easily be discharged. In addition the horizontal drive circuithas a ‘low-power start-up’ function.The vertical ramp generator needs an external resistor and capacitor. For the vertical drive adifferential output current is available. The outputs must be DC coupled to the vertical outputstage.The IC has the following geometry control functions: Vertical amplitude Vertical slope S-correction Vertical shift Vertical zoom Vertical scroll Vertical linearity correction. When required the linearity setting for the upper and lower partof the screen can have a different setting. Horizontal shift EW width EW parabola width EW upper and lower corner parabola correction EW trapezium correction Horizontal parallelogram and bow correction.When the East-West geometry function is not required (e.g. for 90 picture tubes) the EW outputpin can be used for the connection of the AVL capacitor. This function is chosen by means of theAVLE bit.5.2.8 Chroma, luminance and feature processingSomeversionscontaina4H/2H(2D)adaptivePAL/NTSC comb filter. The comb filter isautomatically activated when standard CVBS signals are received.A signal is considered as“standard signal” when a PAL or NTSC signal is identified and when the vertical divider is in themodes ‘standard narrow window’ or ‘standard TV norm’.For non-standard signals and forSECAM signals the comb filter is bypassed and the signal is filtered by means of bandpass andtrap filters.The chroma band-pass and trap circuits (including the SECAM cloche filter) are realised bymeans of internal filters and are tuned to the right frequency by comparing the tuning frequencywith the reference frequency of the colour decoder.