[time-nuts] Temex LPFRS-01 analog frequency adjustement

[Mark Spencer]

Thanks.   I recall seeing documentation that more or less said that directly 
connecting these units to an RS232 port will typically work but is not 
guaranteed.  If you are able to easily check your unit that would be great but I 
will likely try connecting mine to an RS232 port in the next few weeks.
 
I wanted to get a sense of how well the unit is working prior to putting to much 
effort into this.   As it arrived with a circuit board that includes a frequency 
adjust trimmer it was pretty simple to test.
 
 The spec sheet indicates that the smallest frequency step for  RS 232 control 
is 1X10-11, and I was also curious if finer frequency control was possible via 
the analog frequency adjust input.   I suspect that 1 x 10-11 is the limit but 
I'm not 100 percent sure of this.    



----- Original Message ----
From: Magnus Danielson <magnus at rubidium.dyndns.org>
To: time-nuts at febo.com
Sent: Mon, March 7, 2011 9:43:47 AM
Subject: Re: [time-nuts] Temex LPFRS-01 analog frequency adjustement

On 03/07/2011 05:52 PM, Mark Spencer wrote:
> Greetings.  I'm wondering if any one has any insight (or wishes to speculate) 
>as
> to how the external analog frequency adjustment on a Temex LPFRS-01 Rubidium
> standard functions.
> 
> 
>  From experimenting with one over the last few days there seems to be a step
> function to the adjustment.  I'm wondering if frequency adjustment voltage is
> read by an  ADC which is monitored by the CPU which adjusts the frequency ?
> (Or perhaps I'm just not adjusting the multi turn trimmer properly.)

There is a CPU in there with ADC and DACs. You also have serial interface to it, 
so you could hook it up to RS-232. Don't recall from the top of my head if the 
levels is RS-232 or CMOS, but I can check... as I have one.

Cheers,
Magnus

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.