[time-nuts] Low noise power supplies for time nuts circuitry

[Joe Gwinn]

At 2:28 PM +0000 11/24/11, time-nuts-request at febo.com wrote:
>Message: 3
>Date: Thu, 24 Nov 2011 13:22:38 +0100
>From: Attila Kinali <attila at kinali.ch>
>To: Discussion of precise time and frequency measurement
>	<time-nuts at febo.com>
>Subject: Re: [time-nuts] Low noise power supplies for time nuts
>	circuitry
>Message-ID: <20111124132238.0c810b78.attila at kinali.ch>
>Content-Type: text/plain; charset=US-ASCII
>
>On Wed, 23 Nov 2011 04:50:49 -0800
>Chuck Forsberg WA7KGX N2469R <caf at omen.com> wrote:
>
>>  How well would a pair of cascaded 3 terminal regulators do - say a 7815
>>  feeding a 7812.
>
>78xx Regulators are quite noisy. You can use them to filter the
>noise of a cheap DC/DC converter, but i wouldnt use them feed
>high precision electronics. There are a lot better designs these days.

What I see done in low-noise circuits is a low-noise opamp used as a 
linear voltage regulator to clean up the output of a 78xx or the like 
regulator.

Joe Gwinn