| Home |
| Search |
| Today's Posts |
|
#4
July 1st 06, 03:04 PM
posted to rec.radio.amateur.homebrew
|
|||
|
|||
Self-heating of crystal in inverter oscillator
On Sat, 01 Jul 2006 02:23:19 -0500, Ben Jackson wrote:
On 2006-06-30, wrote: From a stability factor point of view those "inverter" based oscillators are amoung the worst. Good to know. I was trying to reduce part count -- the quad XOR provides the two oscillators plus one mixer. and I bet there are parameter shifts in the "chip" as it warms up The other parameter shift I was missing was droop in the 5V rail as the 78L05 warmed up (rapidly!) and noise injected by a MAX202 charge pump also on that 5V rail. I thought that regulator was just for an (unused) LCD header, but I was wrong. Those added elements don't help. However I've used flavors (both TTL and CMOS) of the circuit and stability is only ok at best. One use was a simple freq counter (commercial purchase) and I could never get it to stay zeroed on WWV, it was always 100hz or more off every time I'd check it. I tried everything and finally pulled that out and added a simple transistor circuit. After than the error was usually less than a few hz. I suggest a discrete Bipolar or FET where you can control the operating point of the device better. If I can't tame this VCXO I will try that. This must be how Manhattan prototyping branches off into "Ugly"... It do at that.  Allison |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Forum | |||
| Low current crystal oscillator | Homebrew | |||
| Drake TR-3 transceiver synthesizer upgrade | Homebrew | |||
| Drake TR-3 transceiver synthesizer upgrade | Homebrew | |||
| Crystal Oscillator for 3.560MHz? | Homebrew | |||
| Crystal Oscillator for 3.560MHz? | Homebrew | |||
Threaded Mode
