| ??? 05/06/11 16:48 Read: times |
#182181 - Many many years ago... Responding to: ???'s previous message |
... I had a little application with two simple 74HCMOS RC inverter oscillators of different frequencies. The circuit should work with batteries, but was tested with a proper 7805. During the test everything worked fine. So did with new batteries. But when the time went by and the batteries became a bit "used" the frequencies locked suddenly and were no longer independent!
Ok, I thought, that some individual RC-Filtering of supply voltage at each oscillator would help. But, no, filtering didn't help at all! Even the least noise on signal ground made the two oscillators lock again. Only when I replaced the inverter oscillators by two CMOS-555 the problem of locking could be solved. Kai Klaas |
| Topic | Author | Date |
| An excellent demonstration of coupling between oscillators | 01/01/70 00:00 | |
| Many many years ago... | 01/01/70 00:00 | |
| You don't suppose that was for a reason, do you? | 01/01/70 00:00 | |
| Sensitivity since lack of "mass" to uphold frequency | 01/01/70 00:00 | |
| Even in well-filtered applications ... | 01/01/70 00:00 | |
| Ground bounce... | 01/01/70 00:00 | |
| Length of gnd/vcc "bumps" in relation to period difference | 01/01/70 00:00 | |
| That was an interesting problem | 01/01/70 00:00 | |
| Signetics (later as Philips) made 74HC7046 | 01/01/70 00:00 | |
| That's a really nice demo | 01/01/70 00:00 | |
| One of many | 01/01/70 00:00 | |
| On a similar note | 01/01/70 00:00 | |
| No coupling | 01/01/70 00:00 | |
| Very nice... | 01/01/70 00:00 | |
| Easy if they have a screw adjustment + web cam | 01/01/70 00:00 | |
It remembers me... | 01/01/70 00:00 | |
| huh? | 01/01/70 00:00 | |
| Just different location of screw adjustmenton clock pendulum | 01/01/70 00:00 |