| ??? 05/07/11 13:26 Modified: 05/07/11 13:28 Read: times |
#182190 - Even in well-filtered applications ... Responding to: ???'s previous message |
in the mid-late '70's and into the '80's, the 74S124 dual VCO was very popular in PLL applications for communications and disk drive interfaces, etc. However, it was tempting to use both of the VCO's on the chip, rather than two separate IC's.
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. Now, that wasn't CMOS, yet it was quite severely affected in applications wherein the two VCO's operated at nearly the same frequency, or at different harmonics of a common frequency. 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. RE |
| 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 |