[evlatests] [Fwd: Failures to Tune, at Q-band]

[Ken Sowinski]

Here is my summary of syntheisizer behavior

If standby is asserted, the thing is really not working.
It may work again if a new frequency request is sent, or,
in the extreme case, it may need to be re-booted.

If standby is not asserted it may or not be OK.  It might
be locked on the wrong tooth of the comn, or may not know
that it is not locked.

The lock indicaotr (M_LOCK and C_LOCK) are pretty reliable
indicators of transient behavior when re-tuning, but not
reliable as an indicator of failure to lock.

Using the standby monitor point should flag many cases of broken
synthesizers while not providing false positives.



On Mon, 28 Nov 2011, Bryan Butler wrote:

>
> i had it in my head that we never know if the L302 fails to tune.  at least 
> not generally.  for instance, if it locks on the wrong tooth of the comb, we 
> never know.  i can't say anything about the L301 - nothing is sticking in my 
> RAM on that one.
>
> 	-bryan
>
>
> Rob Long wrote, On 11/28/11 16:34 PM:
>> Ken is right, L301s either lock or they are (hard) broken. When we see
>> "tuning failures", do we actually see L302 lock warnings? I can look
>> into archive data and get a feeling for what the synths are doing (but I
>> can not see frequency).
>> 
>> Rob
>> 
>> Ken Sowinski wrote:
>>> When this happens it is often the case that the module has given
>>> up and placed itself in 'standby' mode which means it will do
>>> nothing until it gets a new command to tune to a different frquency.
>>> I have no way of knowing whther this happens in every case, but I
>>> use it as a diagnostic when troubleshooting non-working antennas.
>>> 
>>> There is a monitor point (obviously enough called 'standby')
>>> to reflect this state.  It could generate an alert which would cause
>>> flagging for the appropriate IF pair.  As a reminder:
>>> L302-1  ->  A0C0 or A1C1
>>> L302-2  ->  B0D0 or B1D1
>>> L302-3  ->  A2C2
>>> L302-4  ->  B2D2