RGB Video Processor and Sync Generator

Overview

The unit has been designed to cater for the different video input requirements for a range of equipment, e.g. monitors, video projectors, plasma screen displays etc.

In particular, the way in which synchronising information needs to be presented to different equipment varies from one item to the next, as there is no one standard applicable to them all. Four switches are provided on the unit to enable the user to select the different processing modes that may be required. The unit also has three LED indicators, which give useful information to the user about the nature of the video signal being processed. The unit has been designed to be installed ‘in line’ with the input signal path of the display equipment and has SCART input and output connections, thus making connection simple.

Product Description:

The unit has been designed to process the synchronising information on the GREEN signal of a RGB video input signal (and also on the Composite video input signal, if this is present). Two 5V logic-level separated sync pulses are also generated within the unit. These may be required by certain types of equipment. The polarity of these pulses can be inverted if required (SWITCH 1). These two generated pulses are Vertical (Field) syncs and Horizontal (Line) syncs respectively. The user can also switch the Horizontal (Line) sync signal to be a Mixed sync signal instead, if required (SWITCH 3).

The unit allows the user to process the video in a number of ways:

Firstly the user can remove syncs from the GREEN video signal if required. Syncs are usually present on the GREEN input signal, but in some cases the presence of syncs here may prevent some video equipment from functioning properly. Thus, the unit provides for these to be removed if required (SWITCH 4). Conversely, in some cases, video equipment may require syncs to be present on the GREEN signal, but these are sometimes absent from GREEN, and may only be present on the Composite video signal instead. To cater for such cases, the user can add sync pulses to the GREEN signal if required (SWITCH 2), the unit deriving this sync information from the Composite signal in this case (assuming this is present).

LED Indicators:

The signal LED’s on the unit provide useful information about the nature of the input video signals to the unit. Two of these LED’s indicate the presence of the Composite signal and GREEN signal respectively. The third signal LED indicates the presence of syncs on the GREEN input video signal to the unit. It is assumed that sync pulses are contained within the Composite video signal whenever present. (Please note that the GREEN signal LED indicates the presence of picture video on the GREEN signal. In such cases where there is zero green picture content in the RGB input signal, this LED will not illuminate.) A fourth LED indicates the presence of power on the unit.

SBBOX

Switch Settings:

The operation of the switches is summarised as follows:

SWITCH 1:                   Sets the polarity of the logic-level separated synchronising output pulses

Switch UP:                   Positive-going pulse outputs

Switch DOWN:             Negative-going pulse outputs

SWITCH 2:                   Allows addition of syncs to the GREEN signal if required

Switch UP:                   Sync addition OFF

Switch DOWN:             Sync addition ON

Note: If the ‘GREEN syncs’ LED indicates presence of syncs on the GREEN input signal (i.e. is ON), it is recommended the above switch be left in the UP position.

SWITCH 3:                   Selects between Horizontal (Line) and Mixed sync on the logic-level separated synchronising output pulse

Switch UP:                   Horizontal (Line) syncs selected

Switch DOWN:             Mixed syncs selected

SWITCH 4:                   Allows user to remove syncs from the GREEN signal if required

Switch UP:                   Syncs removed from the GREEN signal

Switch DOWN:             Disables sync removal from the GREEN signal

Note: If the ‘GREEN syncs’ LED does not indicate presence of syncs on the GREEN signal (i.e. is OFF), it is recommended the above switch be left in the DOWN position.

Additional Information:

No processing takes place on the following signals- RED, BLUE, LEFT AUDIO, RIGHT AUDIO, SCART PIN 8 SWITCH SIGNAL, SCART PIN 16 SWITCH SIGNAL. All of these signals pass through the unit unaffected.

Although the Composite signal is used to derive synchronising pulses within the unit, this signal also passes through the unit without change.

All sync pulses are derived from the GREEN signal where these are present. Should these not be present, the sync pulses are derived from the Composite signal. This process takes place automatically within the unit.

The normal SCART input and output pin formats has been used in the design of this unit. However, on the output SCART, pins 10 and 12 have been used to output the 5V logic-level Vertical (Field) and Horizontal (Line)/Mixed synchronising pulses respectively. (The source impedance of these two pulse outputs is 470R)

The power supply required is a 12V centre positive source (2.1mm)

Broadcast-specified components have been used in the design of this unit, thus giving the highest quality performance.  

Download the instruction manual for this product here

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