Correct signal, nice round curves at the top and bottom.
Clipped signal at the top and bottom of the pattern.
Thursday, December 14, 2006
Laser calibration using an oscilloscope >>>>>
Adjust your oscilloscope and start measuring on the signal point for your board.
Correct signal, nice round curves at the top and bottom.
Clipped signal at the top and bottom of the pattern.
Correct signal, nice round curves at the top and bottom.
Clipped signal at the top and bottom of the pattern.
Laser calibration using an oscilloscope >>>>
Set the scope at 20mV and 0.2us Sweep. The scope must be at least 20Mhz.
When you connect the scope, you should se a clear "eye pattern" signal, like the one above.
When you increase laser power, the amplitude (height) of the pattern will increase. Do not adjust too high, or the pattern will "clip" at the top and bottom.
You will have to test with several different discs/media as all media have different reflectivity. Therefore, if you calibrate the laser so it will be just below clipping with cd-r media, it might "clip" when using originals.
We recommend you take readings from a brand new PS2 to get reference levels. Normal values are 800mV peak to peak with DVD media and 640mV peak to peak with CD media.
When you connect the scope, you should se a clear "eye pattern" signal, like the one above.
When you increase laser power, the amplitude (height) of the pattern will increase. Do not adjust too high, or the pattern will "clip" at the top and bottom.
You will have to test with several different discs/media as all media have different reflectivity. Therefore, if you calibrate the laser so it will be just below clipping with cd-r media, it might "clip" when using originals.
We recommend you take readings from a brand new PS2 to get reference levels. Normal values are 800mV peak to peak with DVD media and 640mV peak to peak with CD media.
Subscribe to:
Posts (Atom)
