| ??? 05/07/11 14:31 Read: times |
#182191 - Ground bounce... Responding to: ???'s previous message |
Per said:
The closer the two frequencies are, the harder it is to manage to filter the supply enough that they will not interfere. The funny thing was, that in my application the frequencies were very different. When the two oscillators locked, the one frequency was an exact multiple of the other. Richard said:
The ground-bounce, however, specifically, that internal to the chip, had the manufacturers cautioning users not to use both VCO's at the same time, as they'd "talk" to one another. Internal ground bounce is also a problem with the popular CMOS4046. It can be of enormous benefit to take two CMOS4046 chips and use only the VCO from the one and only the phase comparator from the other. Richard said:
Today, I wonder if there's even a single VCO to take its place, however. There are plenty of VCO's in the 2.5 GHz range, but few in the 2-to-60 MHz range. I wonder what people are using in their place. The 74HC4046 is often used for frequencies up to 10MHz. 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 |