| 摘要 |
1,248,502. Timing pulses. GENERAL RADIO CO. 1 Jan., 1969 [20 May, 1968], No. 85/69. Headings G4A and G4H. Apparatus for relating a standard pulse rate to the period of an unknown signal has means for automatically adjusting the number of unknown signals sampled. A sample rate control 111 sets a range counter 114 between 1 and 10,000 according to the number of signals at 3 to be counted by counter 7 while clock pulses from a source 1 are fed to a counter 5. The first signal at 3 following a command from 111 sets flip-flop 113 to 1 to open gates 2<SP>1</SP>, 2<SP>11</SP>. Assuming that range counter 114 is set to 1 then gates 93-96 are open so that the next pulse from 3 opens AND gate 116 to restore flip-flop 113 to stop the count of clock-pulses. If the count in counter 5 has not reached the order 51 the value is too coarse and the absence of a signal from OR gate 91 operates AND gate 117 to step the range counter 114 up and a new measuring cycle starts based on ten signals from 3. Control of flip-flop 113 is now dependent on gate 93, and so on. If the range counter 114 is set too high, carry takes place from the highest denomination of counter 5 setting flip-flop 92 to stop the count and stepping the range counter 114 down. The result of count at 5 may be inverted to provide a reading in frequency. |
