[time-nuts] thunderbolt fault

[WarrenS]

>>Common mode choke filter does not get ride of LINE NOISE on the +12 V or 
>>LINE VOLTAGE sensitivities...,
>Please explain how a common mode choke on the +12 and ground does nothing 
>to help keep the supply clean.


What size is your common mode choke filter?
To have any effect on 60 Hz PS ripple it would need to bigger than a (small) 
bread box .
And to help reduce DC type line voltage variations it would need to be 
bigger than a planet. (yea, Earth size)
Common mode filters are for HI freq, not 60 Hz OR DC.
But then, you already know that so I do not know why your comment???

ws
*************
Hi

Please explain how a common mode choke on the +12 and ground does nothing to 
help keep the supply clean.

Bob
*****************

On Feb 26, 2010, at 9:57 PM, WarrenS wrote:
>
>> Lots of questions ....
> Same Simple answer.
> Make the +12 volts is as good as you can get it, For the rest any general 
> purpose PS works fine.
> And a Common mode choke filter does not get ride of line noise on the +12 
> V or Line voltage sensitivities, both are important on the +12V
>
> ws
>
> ****************
> Hi
>
> Depending on the supply setup, a common mode choke might also be a good 
> idea.
>
> The +12 runs the OCXO, so it's going to have an impact.
>
> What about the +5 Volts? Obviously it needs to be crud free. Gross changes 
> will impact the temperature of the unit. What about small changes? Is it 
> running the maser reference for the DAC or does that come off the +12? Is 
> +5 just a digital supply?
>
> Lots of questions ....
>
> Bob
>
> On Feb 26, 2010, at 6:59 PM, WarrenS wrote:
>
>>
>>
>> Yes, I Did that,   The +5 and -12 has NO effect on freq or operation of 
>> the unit except for really far out voltages.
>> I tested mine with the -12 from -2 to -15 and could see no effect in the 
>> e-11 range.
>> The -12 is used for the RS232 and the -Dac out so If you don't need the 
>> neg Dac out voltage or neg RS232  Drive, then it can pretty much be 
>> anything. But It should be kept in -7 to -13 range, and common sense 
>> means there should be little noise on it so it does not couple into other 
>> things. BUT the circuit it's self does not care what the supply is at or 
>> what is used.
>>
>> The +12 on the other hand, Needs to be stable and quiet with no ripple.
>> I found using a +15 volt supply feeding a 12V three terminal will heat 
>> slinked regulator a good way to go to keep ALL the ripple out of the +12V
>>
>> ws
>>
>> *******************
>>
>> Hi
>>
>> Has anybody actually measured the supply sensitivity on the -12 volt line 
>> to see weather a 5 volt change makes any noticeable difference in the 
>> output frequency? The power on -12 is very low, so there should be 
>> negligible thermal impact from a change.
>>
>> Bob
>