Re: [time-nuts] NIST isolation amplifiers

The magnetic field in the core due to the current in the windings is proportional to current times number of turns.  If there are more than one winding, add the currents.  Yes, 2 x 20mA certainly exceeds 30mA.   The core will be driven closer or into saturation and the inductance will be

Re: [time-nuts] More FE5680 GPS Disciplined Controller

Hi Bert, Welcome back. I'm willing to help on the LCD interface code, if you'll send me-- (1) a schematic of the board, (2) a datasheet on the LCD (or link to where I can get one) --that includes information on control and data interfacing (3) any existing code for this PIC (so I can

Re: [time-nuts] GPSDO and holdover

Some timing GPS units (eg Oncore UT) can be set to omit 1PPS pulses if no satellites are being tracked, or if the RAIM alarm limit is exceeded. Dave On 4/25/2014 10:20 AM, Paul wrote: On Tue, Apr 22, 2014 at 9:57 PM, Tom Van Baakt...@leapsecond.com wrote: I have noticed skipped 1PPS on the

Re: [time-nuts] Is this ocxo salvageable?

The output looks differentiated, as would happen if the wire connecting the internal circuit to the output pin became open, leaving only a very small capacitance to couple the square wave out. Dave On 4/8/2014 11:46 PM, Chris Albertson wrote: My Bliley square wave 10MHz OCXO was working just

Re: [time-nuts] Photodiodes for high frequency OPLL

You'll need a photodiode that can detect photons at your lasers' wavelength. You may be able to use a photodiode at a shorter than its design wavelength as long as there are not coatings (eg anti-reflection) that block the wavelength of interest. You'll need to make sure that both lasers

Re: [time-nuts] Nifty MINI TIC for DMTD work detail Info please read

Hi Bert, What kind or sort of documentation is needed? schematics? PC layout? software / firmware documentation? I've been programming PICs intermittently for 10+ years. Some of my projects use 2 or 4 line LCD displays. I have given other microcontrollers a short test spin. I've also done

Re: [time-nuts] getting a grip on 10811 drift (beginner-ish question)

If you can measure the 10811 frequency as a function of the control voltage with the 10811 control voltage input disconnected from everything else, you'll have a curve that will allow you to translate control voltage changes into frequency drift. My impression is that the 10811 ageing is

Re: [time-nuts] New atomic clock

The article was accepted for publication on Feb 22, 2012in Physical Review Letters. The March issue has already been published, so maybe this one will be in the April issue. The title is Single-ion nuclear clock for metrology at the 19th decimal place Authors: C. J. Campbell, A. G.