evans@mhuxt.UUCP (crandall) (04/20/85)
For what its worth a fellow in my group at Murray Hill mentioned that he and another fellow built a "light beam" stylus in the late 50s to make a gee-whiz demo for a single tube 8 bit ADC (it had an internal shadow mask!) they were working on. He reports that the thing produced crediable sound. Tracking was via a non-functioning stylus as they didn't have time to build a photo-tracker. Steve Crandall AT&T Bell Labs ihnp4!mhuxt!evans
dca@edison.UUCP (David C. Albrecht) (04/23/85)
> For what its worth a fellow in my group at Murray Hill mentioned that he and > another fellow built a "light beam" stylus in the late 50s to make a gee-whiz > demo for a single tube 8 bit ADC (it had an internal shadow mask!) they were > working on. He reports that the thing produced crediable sound. Tracking was > via a non-functioning stylus as they didn't have time to build a photo-tracker. > From time to time I have wondered on the practicality of using laser beams to track a traditional record rather than a contact method stylus. Not knowing that much about lasers or an electronic wizard it never got beyond pure speculation. If it was possible to get enough reflection off the record to accurately reproduce the cut signal maybe it would also be possible to do a reasonable job of integrating the signal to eliminate large excursions caused by pits, scratches, and dust. David Albrecht General Electric
ron@brl-tgr.ARPA (Ron Natalie <ron>) (04/26/85)
> From time to time I have wondered on the practicality of using laser beams > to track a traditional record rather than a contact method stylus. Not > knowing that much about lasers or an electronic wizard it never got beyond > pure speculation. If it was possible to get enough reflection off the > record to accurately reproduce the cut signal maybe it would also be > possible to do a reasonable job of integrating the signal to eliminate > large excursions caused by pits, scratches, and dust. > And what's interesting, is that the job of avoiding scratches may be aided by the fact that the laser does not need to read the disk in real time. -Ron