[time-nuts] Re: Austron Oscillator Products

[john.haine at haine-online.net]

GSM standards development started in 1982 though there was prior work in several labs.  Basic phy layer parameters were probably fixed by 1985 as the development cycle was quite long drawn out (especially for handsets as the "long pole" went through the tester!).  Networks were launched in 1991 so devices must have been in procurement several years before then.  When were these devices made?  I think they might have locked BTS clocks to the incoming PCM 2.048 Mbit/s links, not sure about the RF, though given the way all the numbers are interrelated they might have had to.

-----Original Message-----
From: Bob Camp via time-nuts <time-nuts at lists.febo.com> 
Sent: Wednesday, February 28, 2024 2:09 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Cc: Bob Camp <kb8tq at n1k.org>
Subject: [time-nuts] Re: Austron Oscillator Products

Hi

If you dig around with Google, there are other similar parts at various “random” frequencies in the 50 to 55 MHz range. Best guess is that these went into something other than a GSM ( = fixed clock ) sort of system. The other minor gotcha in terms of GSM is that they shipped a bit before GSM was “invented”  :) :). 

Bob

> On Feb 28, 2024, at 7:02 AM, john.haine--- via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> 52MHz might have been made for GSM base stations.  The GSM numerology 
> works out based on a 13MHz oscillator being needed in a handset to 
> generate all the clock frequencies required.  In a base site a higher 
> frequency could be useful for the more complex signal processing 
> needed.  IIRC my GSM days 13MHz VCTCXOs were common for handsets - 
> frequency would be locked to incoming downlink through the "F bursts" 
> so a relaxed spec could be used (1ppm IIRC).  With GSM precise locking 
> between base stations wasn't so critical, whereas with CDMA using soft 
> handover and more recent standards it becomes essential hence the use of GPS.
> 
> -	John
> 
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