| ??? 01/07/09 14:27 Read: times |
#161364 - CRO Frequency Measurement Responding to: ???'s previous message |
As Erik has stated it may be possible to see frequency jitter of the 555 circuit on the CRO (cathode ray oscilloscope). The best way to increase visual frequency measurement on a CRO is to slow down the sweep so that as many cycles of the signal that you can still discern are across the width of the scope grid. Then carefully count the number of pulses and compute frequency from this count and the scope sweep time across the whole display.
This cramped display will also be likely to show you if there is short term jitter in the 555 frequency as 1% of variation will be much more obvious with 40 or 50 cycles on the screen as opposed to 1 or 2. Michael Karas |
| Topic | Author | Date |
| Frequency (Event) Counter Problem | 01/01/70 00:00 | |
| less than 1% error | 01/01/70 00:00 | |
| Error % is incremental. | 01/01/70 00:00 | |
| ;STARTING BOTH THE TIMERS AT THE SAME TIME | 01/01/70 00:00 | |
| Less variations in TL0 but still error | 01/01/70 00:00 | |
| I do not know, but | 01/01/70 00:00 | |
| CRO Frequency Measurement | 01/01/70 00:00 | |
| Better But Still An Issue | 01/01/70 00:00 | |
| How stabile is your signal source? | 01/01/70 00:00 | |
| Very Good Point... | 01/01/70 00:00 | |
| Easier if 89c52 is used | 01/01/70 00:00 | |
| How stabile is your signal source? | 01/01/70 00:00 | |
NE555 is popular but not a precision device | 01/01/70 00:00 |