| 968 / | HD | HOROLOGY |
| 851 | DD | APPARATUS FOR MEASURING UNKNOWN TIME INTERVALS BY MEANS NOT PROVIDED FOR IN SUBCLASS 817 TO SUBCLASS 844 [G04F 13/00] {3} |
| 852 | DD | .~ Using optical means [G04F 13/02] {2} |
| 854 | | .~.~ Measuring duration of ultrashort light pulses, e.g., in the picosecond range, etc; particular detecting devices therefor (nonlinear optics G02F 1/35; monitoring arrangements for lasers in general H01S 3/00D; photometry, radiation pyrometry G01J 1/00, 5/00) [G04F 13/02C] |