[time-nuts] Looking for info about first true radio controlled clock

[EB4APL]

Hi,

NASA used this code for time tagging the analog tape instrumentation 
recordings.  They also developed slower time codes to be used in strip 
chart recorders ( ie. Nasa 28 bit if my memory doesn't fail).

Regards,
Ignacio


El 22/02/2011 21:12, Magnus Danielson escribió:
> Hi Jim!
>
> On 02/22/2011 02:34 PM, jimlux wrote:
>> On 2/21/11 10:12 PM, Michael Lombardi wrote:
>>> I'm trying to determine the first product that could automatically
>>> decode and display a digital time code. Digital time codes were
>>> added to WWV in 1960 and WWVB in 1965. This was before they were
>>> added to any satellite signals, or before they were added to LF
>>> stations in Europe, such as DCF77. Telegraphic time codes, of
>>> course, were around much earlier.
>>>
>>
>> the IRIG standaards started in the late 50s, and I'm pretty sure that
>> they used time code when recording on instrumentation recorders earlier
>> than that. You'd record a bunch of analog signals using FM on a
>> multitrack recorder, and because the playback speed varies and the tape
>> stretches, you need something to recover actual timing.
>
> The NASA 36 bit time-code seems to pre-date both IRIG and WWV broadcast.
>
> The original WWV broadcast where in fact done in the NASA 36 bit 
> time-code.
>
> "STANDARD FREQUENCY AND TIME SERVICES"
> http://tf.nist.gov/general/pdf/1746.pdf
>
> I have yeat not found the NASA time code history or for that matter 
> the NASA standard for it.
>
>> the first instrumentation recorders were used in the late 40s or 
>> early 50s
>>
>> there's also a famous spread spectrum system used during WW2 with
>> identical phono records with random noise, but I think those were sync'd
>> by hand.
>
> They where synced by hand, but the turn-tables ran on synchronous 
> motors locked to a common frequency broadcast, so the system had an 
> external (common) frequency steering.
>
> Cheers,
> Magnus
>
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