Timeline for How to remove non-square noise from Pierce oscillator?
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
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| Jan 16, 2018 at 21:35 | comment | added | D.A.S. | @Olin I do not think it is is possible to get 7.3728MHz but certainly a clean but unstable 4.xxxMHz, something is inconsistent in the question. | |
| Jan 16, 2018 at 21:22 | comment | added | Olin Lathrop | @Tony: I think both things are going on. The crystal is definitely ringing at 4x the fundamental, largely due to the bad choice of driver. However, the power supply also seems to be effected. See comment from OP above. He put a bypass cap on the power line and most of the artifacts went away. The crystal is still be driven badly and ringing, but that no longer shows up in the output due to the stable supply voltage. | |
| Jan 16, 2018 at 19:05 | comment | added | D.A.S. | @OlinLathrop Its not affecting supply , it is just the signal of an astable at lower f and ringing >2V at Xtal f. Wrong technology. | |
| Jan 16, 2018 at 18:44 | comment | added | Olin Lathrop | @Tony: Yes, see the second to last paragraph of the answer. | |
| Jan 16, 2018 at 17:32 | comment | added | D.A.S. | Can't anyone else see the fundamental flaws errors with this design. The signal is clearly TTL with high impedance resonance above 2V and you must use this LS14 with this design. It must be CMOS linear. TTL output impedance is non-linear. Low at 0V medium at 2V and high above 2V. | |
| Jan 16, 2018 at 7:16 | comment | added | Oskar Skog | There are DIP sockets with built in bypass capacitors, those might be worth looking into. | |
| Jan 16, 2018 at 2:53 | comment | added | user105652 | +1 for getting to the point-in a round about way. Your last 2 paragraphs get to the essence of the problems. Lack of bypass caps and a design that rings like a bell. Someone else gave you a -1. Not sure why... | |
| Jan 15, 2018 at 23:04 | comment | added | Olin Lathrop | @Tom: It's OK to be learning and asking about things new to you. But don't ask about more advanced concepts when you skipped over or are still confused by basic things like bypassing. If you're not sure what that is, then ask about that. It's like asking how to change the piston rings when you're not sure how to use a wrench. It's OK not to know how to use a wrench, but then ask about that before getting into things that assume you know wrench usage. | |
| Jan 15, 2018 at 22:58 | history | edited | Olin Lathrop | CC BY-SA 3.0 |
added 587 characters in body
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| Jan 15, 2018 at 22:55 | comment | added | TomServo | I moved the power connections to another schematic sheet. Thanks for the rule of thumb, that makes perfect sense and when I added the 1uF capacitor most of the AC artifacts went away. | |
| Jan 15, 2018 at 22:52 | history | answered | Olin Lathrop | CC BY-SA 3.0 |