btw the part number for that sled is KMS-260B (not Y090A), common to 1996-8 era ATRAC 4 machines. If you want basic delve into the prior 3 generations of optical pickups / circuit designs ;)
Like CD's there are two side beams on the photodetector used for focus and tracking servo signals. The additional two are refered to as the I and J beams, they are there for re-recordable discs to take advantage of the Kerr effect and detect the polarization of the reflected laser. Depending on polarity one of the beams will be stronger / weaker than the other and a simple subtraction will show whether a 1 or 0 should be interpreted.
This is very interesting. As an American kid living in Germany, I bought my first and only mini disc player. Now as an adult, I work on HAMR recording in HDDs. I didn't realize how mini disc players also leveraged the physics of heating a magnetic media above the Curie temperature to write data. Cool!
Nice! Several of us have been doing work on the NetMD side, but none of us have any experience with the optical side of things, so it's nice to see some other people working on MD stuff!
This is awesome. As a Teenager in the 90s, I really desired a Mini-Disk recorder. It was very much out of my price range. By the time it wasn't that desire was removed, thanks to writable CDs and MP3 encoding.
btw the part number for that sled is KMS-260B (not Y090A), common to 1996-8 era ATRAC 4 machines. If you want basic delve into the prior 3 generations of optical pickups / circuit designs ;)
Like CD's there are two side beams on the photodetector used for focus and tracking servo signals. The additional two are refered to as the I and J beams, they are there for re-recordable discs to take advantage of the Kerr effect and detect the polarization of the reflected laser. Depending on polarity one of the beams will be stronger / weaker than the other and a simple subtraction will show whether a 1 or 0 should be interpreted.
More info: https://web.archive.org/web/20210506190802/https://www.gammaelectronics.xyz/dat_4e_17.html
This is very interesting. As an American kid living in Germany, I bought my first and only mini disc player. Now as an adult, I work on HAMR recording in HDDs. I didn't realize how mini disc players also leveraged the physics of heating a magnetic media above the Curie temperature to write data. Cool!
Nice! Several of us have been doing work on the NetMD side, but none of us have any experience with the optical side of things, so it's nice to see some other people working on MD stuff!
This is awesome. As a Teenager in the 90s, I really desired a Mini-Disk recorder. It was very much out of my price range. By the time it wasn't that desire was removed, thanks to writable CDs and MP3 encoding.