How to Connect the Pixel Clock?
This topic describes the recommended way to supply a pixel clock from the camera to a Domino Iota or a Domino Alpha 2 board.
Connecting a TTL pixel clock signal
Consider the case of a camera delivering the pixel clock in a TTL compliant format with enough strength to feed a 100Ω terminated line.
The present recommendation yields the best signal integrity as well as the best electromagnetic compatibility performance.
The adequate jumper configuration corresponds to the strapping involved when JumperCK is valued CKDPOS or CKDNEG.
Refer to the following simplified electrical drawing.
This drawing shows that the TTL pixel clock signal coming from the camera should be transported by means of a coaxial or shielded cable. A possible choice is RG179.
The video cables and other control lines linking the camera to the board are preferably grouped into a single composite cable, equipped with an overall shield.
The overall shield should not enter in contact with the pixel clock cable shield. In other words, the clock cable is externally insulated.
The overall shield is electrically connected to the camera body through the conductive camera connector. On the board side, the overall shield is connected to the HD15M conductive shell.
Connecting a RS-422 or LVDS pixel clock signal
Consider the case the case of a camera delivering the pixel clock in true differential format with enough strength to feed a 100Ω terminated line. RS-422 and LVDS standards are such cases.
The present recommendation yields the best signal integrity as well as the best electromagnetic compatibility performance.
The adequate jumper configuration corresponds to the strapping involved when the MultiCam parameter JumperCK is valued CKDPOS or CKDNEG.
Refer to the following simplified electrical drawing.
This drawing shows that the differential pixel clock signals coming from the camera should be transported by means of a twisted pair line. The best situation corresponds to a pair with a 100Ω differential characteristic impedance.
The video cables and other control lines linking the camera to the board are preferably grouped into a single composite cable, equipped with a mandatory overall shield.
The overall shield is electrically connected to the camera body through the conductive camera connector. On the board side, the overall shield is connected to the HD15M conductive shell.