JVC Model 200 service manual Raster Timing Generator PCB

Chapter 2---System Description

2.3.7 Raster Timing Generator PCB

The Raster Timing Generator (RTG) is located in the electronic card cage (Figure 5-1). The RTG I/O diagram (Figure 2-13) and the list of inputs and outputs (Tables 2-10 and 2-11) provide information to allow the technician to perform module level troubleshooting.

The following functions are provided by RTG board:

•Internal sync generation

•Sync detection and selection

•Serration and equalization pulse removal

•Phase locked loop

•Blanking pulse generation

•Horizontal and vertical phase adjustments

•Interlace detection and odd field pulse generation

•Horizontal frequency band selection

•Horizontal line count and vertical count generation

•IIC interface

•Video clamp pulse generation

•Source change detection

•HVPS sync generation

•Horizontal deflection enable circuitry

The RTG I/O Diagram (Figure 2-13) and the list of inputs and outputs (Tables 2-7 and 2-8) provide information for the technician to perform module level troubleshooting.

Horizontal frequency band selection and LED logic.

The RTG produces a voltage that is proportional to the horizontal frequency which is used by the Horiz/Vert Deflection board, System Controller Board, and the phase locked loop (PLL) section of the RTG board. This DC voltage is used to create the following frequency bands:

Band A: from 15 KHZ to 24.5 KHZ.

Band B: from 24 KHZ to 29.5 KHZ

Band C: from 29 KHZ to 56 KHZ

Band D: from 55.5 KHZ to 90 KHZ.

These bands are outputted through the IIC interface to be used by the System Controller Board. These lines are also outputs of the RTG board through the Backplane Board. The

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