[time-nuts] KS-24361 adjustable PLL time-constant

Bob Camp kb8tq at n1k.org
Sat Dec 20 13:26:33 EST 2014


Hi
> On Dec 20, 2014, at 10:26 AM, Ole Petter Ronningen <olepr01 at gmail.com> wrote:
> 
> I know these has been discussed to death here, so my apologies for that.
> Also, apologies if this has already been reported; i did not find it in the
> archives..

You are the first to dig into the PFORTH side of this box. 

> 
> It might be of interest to some that it appears that the KS-boxes has an
> adjustable PLL time constant:
> 
> :SYST:LANG "PFORTH"
>> pll_rep
> start ptr = 0    stop_ptr = 0
> max loop time = 700
> ffom = 1
> tfom = 1.0e-06 secs
>> 1000 loop_time
>> pll_rep
> start ptr = 0    stop_ptr = 0
> max loop time = 1000
> ffom = 1
> tfom = 1.0e-06 secs
> 
> Looks like a teakable PLL parameter, but I don't have the measurements to
> back it up. Yet.

The key would be to find the magic report that shows the current PLL setting. They likely push it out to max a bit at a time. If it does get to the max, then indeed bumping it up might be a good idea. Something like “current pull” could be the key here. 

To have full control you also would need to find the table (or formula) for the P,I, and D values associated with each time constant. 

> 
> Also, there is a command to report on the L1-status, which might make life
> easier for those who try to get the boxes going separately by manipulating
> the J5-port:
> 
> On REF-0
>> print_l1
> mode: locked, duration: 1152
> locked duration: 1153, learning exceeded: 0
> ready: 1, critical failure: 0
> shutdown failure: 0
> GPS locked once: 1
> GPS found once: 1
> Flywheel capable state: 0, time: 3600 sec
> Other flywheel capable state: 2, time: 28800 sec

that one suggests that the two boxes know a bit about each other. It’s also possible they simply are timing the same event.

> flywheel ready mode: idle
> Other GPS locked once: 1
> other on: 1, delayed other on: 1

Delayed on probably is the flash back and forth sequence at startup. 

> 
> Monitor
> enable active: 1, ready: 1, hold actref: 1
> ext_1pps_dead: 1 ext 1pps valid: 0
> gps_1pps_dead: 0 gps 1pps valid: 1
> 
> HW lines
> cable 1, active in: 0, ready in: 1
> Ext locked in: 0, GPS Locked once in 1
> ACTREF out: 1, PRI_ACT out: 1
> Int power: 0, Ext power: 0

A bit of work could put names with the pins on the connector. Here are a few guesses:

cable = pin 3, goes to ground on pin 13 on ref-1, low is shown as 1 in the report above
int power = pin 10, goes to pin 6 on ref-1, (17/23 dbm switch), low shown as 0 in the report above
ext power = pin 6, pin 10 on ref-1,                   “
ACTREF out = 
Ext locked =    
Ready in = … (guess 2,14 below, low reported as a 1)

signaling pairs left are:

2,14 	(low,low)
4,12		(low ,high)
7,9		(low,high)

Simply based on the (low,low) the Ready in / out pair would appear to be 2,14. That’s on the assumption that both report the same (see below).

It’s a coin flip in terms of the other two. 


> -----------------
> 
> on REF-1:
> mode: locked, duration: 76342
> locked duration: 76343, learning exceeded: 0
> ready: 1, critical failure: 0
> shutdown failure: 0
> GPS locked once: 1
> GPS found once: 1
> Flywheel capable state: 2, time: 28800 sec
> ref duration: 100
> other on: 1, delayed other on: 1

That’s not the same report as the other one. The boxes know what they are and run different code or the report changes based on who’s active.

> 
> Monitor
> enable active: 1, ready: 1,

ready out shows the same as ready on the other box. 

> hold actref: 0
> ext_1pps_dead: 0 ext 1pps valid: 1
> gps_1pps_dead: 0 gps 1pps valid: 1
> 
> HW lines
> cable 1, active in: 1, ready in: 1

ready in shows same as the other box

Bob

> ACTREF out: 0, PRI_ACT in: 0
> Int power: 0, Ext power: 0
> 
> 
> OleP
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