Special Operating Modes
Probe Sync Pulse Output
The FS connector on the sync module can output a TTL Level probe pulse that can be used to trigger an oscilloscope or to synchronize a camera used in automated vision systems. The pulse can be positioned manually by the operator or by commands sent by a test
system. The horizontal timing can be set to a given pixel clock cycle relative to either the horizontal sync pulse or the start of active video for a given line. The vertical timing is set to a given scan line relative to either the vertical sync pulse or the start of active video in the frame. A marker can be added to the video outputs when the pulse occurs during the active portion of the video test signal.
Example of Using the Probe Pulse Feature
Let’s say the image displayed on the monitor looks bad at (900; 200); i.e. it is bad on active line # 200 at active pixel # 900 on that line. You can set the probe pulse to trigger an oscilloscope to look at the video signal for that position as it passes through the monitor’s circuits.
Manually Operation of Probe Pulse Feature
1 ) Turn the test signal outputs off using the “Outputs” button (if not already off).
2 ) While holding down the “Image/Step” Button, press the “Outputs” button to turn the outputs on.
3)The generator will output the same video format and test image that were last selected. The LCD window will change to the Probe Pulse User Interface shown here. The video and sync gating buttons get new functions in this operating mode. You can not use the buttons to gate colors or change sync gating when the probe pulse feature is active.
P:nnnn X:nnnn L:nnnn Y:nnnn
The number after “P:” is the position of the probe on a given scan line relative to the leading edge of horizontal sync measured in pixel clock cycles. The number after “L:” is the number of the scan line relative to the leading edge of vertical blanking. For interlaced formats the line number is relative to the start of blanking for the first field. If the horizontal probe position is within the active area of the screen, then the X coordinate of the pixel (X:nnnn) is also displayed. Likewise, if the vertical position of the probe is in the active area, then the Y coordinate of the line (Y:nnnn) is also displayed. For interlaced formats, the L count will move the probe in consecutive lines in one field of video and then move on through blanking and the next field of video. This will cause the Y count to increment in steps of two.
The Format knob adjusts the “P:nnnn” horizontal timing probe position, while the Image knob adjusts the “L:nnnn” vertical timing probe position. The knobs have an exponential taper which is reset whenever the knob reverses direction. This feature provides boath coarse and fine adjustments (i.e. you do not have to rotate the knob a thousand times to get to where you are going.). You can also use the sync gating buttons lock which digits are changed by the knobs. Pressing the “ACS” button will cause the knobs to step the counts in 100 unit increments. Pressing the “DCS” button will cause the knobs to step the counts in 10 unit increments. Pressing the “DSS” button will cause the knobs to step the counts in 1 unit increments. Pressing the same button a second time will revert the knobs to exponential operation.
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