| 968 / | HD | HOROLOGY |
| 901 | DD | PRODUCING TIMING PULSES (driving circuits for stepping motors subclass 490; producing preselected time intervals for use as timing standards subclass 817; pulse technique in general H03K; control, synchronization, or stabilization of generators in general H03L) [G04G 3/00] {1} |
| 902 | DD | .~ Circuits for deriving low frequency timing pulses from pulses of higher frequency (pulse frequency dividers in general H03K 23/00 to 29/00) [G04F 3/02] {3} |
| 905 | | .~.~ By combining pulse trains of different frequencies, e.g., obtained from two independent oscillators or from a common oscillator by means of different frequency dividing ratios, etc. (synchronization of electric timepieces subclasses 506 and 920) [G04G 3/02E] |