[time-nuts] Why a 10MHz sinewave output?

Bob Camp lists at rtty.us
Wed Feb 8 17:15:02 UTC 2012


Hi

Some (but by no means all) gear actually looks at some of the data fields on
the T1 before it will accept it as a reference. In most cases a bits clock
does fine. Of course you do need a proper balanced line driver and all that
stuff to get it running. 

Still not something that's readily available in my basement. At work - not a
problem. 

The simple / stupid way to do it is to use a framer chip. They are cheap
these days and they have all the driver stuff built in. They will even pack
the data fields with "hey, I'm a good clock - use me". Run a cheap PLL to
generate the framer clock and you are up and running. 

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of J.D. Schoedel
Sent: Wednesday, February 08, 2012 1:52 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Why a 10MHz sinewave output?

Hal Murray wrote:
> lists at rtty.us said:
>   
>> Thank goodness for that inertia. I can still cable up a 100Kcps sine wave
>> standard to run stuff from "long ago". When I run into a box that uses a
T1
>> signal for a clock reference - not so easy in the basement. 
>>     
>
> How much gear is there that uses T1 for a clock input?
>
> Is there any interest in a board/chip/whatever that converts 10 MHz to T1?
A 
> clean design using a decimal DDS should fit into a small FPGA, maybe a
CPLD.
>
>   
There  is quite a bit of telecom gear that will take a T1(or E1) as a 
clock reference.  A T1 BITS will provide an all 1's AMI signal which 
looks like 772 kHz on a scope. 

_______________________________________________
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.





More information about the Time-nuts_lists.febo.com mailing list