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[time-freq] Still not there.

Steven Bible n7hpr at tapr.org
Sun Aug 20 16:40:18 UTC 2006


Hi Bobby,

In looking at your jumper settings from your first email, you said: All N &
R dividers are pulled up except R0 which is pulled down.

I have a Reflock II connected to a HP 10811 OCXO and M12 GPS.  My jumper
settings are as follows (from r2_enhpps_30_1.txt):

* f_conf(1),f_conf(0) are the configuration bits for the frequency lock
points.
  ( located at jumper positions N1 and N2 )

	-- f_conf=00 locks to 5KHz multiples (internal divider = 5000)

* avg_conf(1),avg_conf(0) are the configuration bits that select the number
of
  samples averaged. Output is allways updated every second.
  ( located at jumper positions N4 and N8 )

	-- avg_conf=00 average is off, each time lag value is output to PWM DAC.

* 1pps signal polarity selection
  (located at jumper N2048)

	pps_pol = 0 >> rising edge of 1pps is used

The * ld_conf(5-0) is the lock detector threshold selection (located at
jumper positions R0 to R5) is only for indication on LED1 and 2.  It has
nothing to do with the lock.

In summary, all my jumpers are pulled up (which means I have a 10K ohm
resistor in the "1" position) in all jumpers.  I have a 0 ohm resistor in
the "0" position at: N1, N2, N4, N8, N2048.

Finally, the PD2_I or PD2_N depends on your Rb.  It should be in N = normal
if the frequency goes up with tuning voltage going up, or I = invertered if
the frequency goes down when tuning voltage goes up.

I hope this helps.

73,

- Steve, N7HPR
 (n7hpr at tapr.org)



-----Original Message-----
From: time-freq-bounces at lists.tapr.org
[mailto:time-freq-bounces at lists.tapr.org]On Behalf Of Bobby
Sent: Saturday, August 19, 2006 3:42 PM
To: time-freq at lists.tapr.org
Subject: [time-freq] Still not there.


Hi Luis,

I've loaded the 30_1 version, but not really much difference.

LED1 still stays on all the time.
LED2 now flashes off once every 8 seconds (every few times it waits 15) of
so instead of every 15 before.

The reflockII tune voltage still jumps above the 2 V level (coincides with
led2 flashing off) and drifts back down in
about 0.1V increments each second until it either reaches or passes through
the 2V level. Sometimes
it will smooth out slightly for a few seconds around the 2v level, but then
jumps again to about 2.5V
when the 8 (or 15 seconds are up).
If I choose instead to place the jumper at PD_I instead of PD_N the
direction of the steps just reverses,
everything else remains the same.

The 2V level is significant only in that is the tuning voltage my Rb osc is
at when it outputs 10000000
(without the reflock connected) .

I just changed R22 to 39K and it swings a full volt above the 2V level, but
no other change.
Perhaps I'm going the wrong way and this is changing too fast for the loop,
and a large RC to integrate
the steps into much slower (or smoother) rate of tuning change is the
ticket. Hard to see 8 seconds as
too fast though.

Trivia: If I turn off the Rb osc, the reflock tune voltage rails high. Any
help there ?

Any suggestions ?

73 Bobby   k4bga





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