[GPS_Standard] Frequency control range

[Bert, VE2ZAZ]

Hello again Mike,

The item you are pointing to on Ebay is not the same beast that you
described in your previous posting! You referred to TCO-6730 but the one on
Ebay is TCO-6703. No specs are available on the Epson-Toyocom website so we
don't know what it is capable of or what electronic tuning range it has got.
More or less a surprize box, but the price is right...You should ask the
vendor for a specsheet. One thing we see though is that there seems to be a
hatch on the side panel, most likely a mechanical tuning screw...

Regarding the adder, yes, it would be possible to add an offset bias and
reduce the tuning sensitivity on the GPS Standard opamps. You would have to
be careful not to introduce any additional noise that would modulate the
oscillator. Careful design would certainly work.

Have fun.

Bert, VE2ZAZ

----- Original Message -----
From: "Mike W" <mike at pencoys.org.uk>
To: "Bert, VE2ZAZ" <ve2zaz at sympatico.ca>
Sent: Friday, July 13, 2007 3:33 PM
Subject: Re: [GPS_Standard] Frequency control range


Thankyou for your time in looking at the spec Bert, and also for your
comments
in reply to my request about suitability.
On the freq adjustment point, and I'm not up to much with Op-amps, but I was
thinking of an adder circuit, one op-amp input with a Pot to set frequency
and
the other input taking the controller output.
They are currently available on Ebay UK, Item number No.180138004701
present status 5 days to go, current price 10 UKP.

73, Mike

On 13 Jul 2007 at 8:04, Bert, VE2ZAZ wrote:

> Hi Mike,
>
> I have looked at the specsheet for the Toyocom TCO-6730 and its tuning
> range
> is indeed badly specified. To me, VC=5V +/-5V probably means 0 to +10V
> tuning voltage. Calling them up would be the only way to confirm...
>
> Otherwise, it appears to be useable on the GPS-Derived Frequency standard.
> The aging and stability specs compare favorable to the HP 10544 series.
The
> tuning is broader (6Hz) than the HP series OCXO (1Hz), but I have tested
my
> system with a 10Hz tuning range and it met the specified accuracy. It uses
> a
> single supply, which simplifies hookups. The unit does not have a
> mechanical
> frequency adjustment though, so this is probably one drawback, as you will
> not be able to adjust it to the DAC voltage center point. But they
> guarantee
> that the electronic tuning will always be able to bring it to the nominal
> frequency, so...
>
> Do you have any idea of how much this sells for? I am sure it is not cheap
> in quantity of one. For similar price range, I think I would still prefer
a
> HP unit...
>
> Best Regards,
>
> Bert, VE2ZAZ
>
> ----- Original Message -----
> From: "Mike W" <mike at pencoys.org.uk>
> To: <gps_standard at mailman.qth.net>
> Sent: Thursday, July 12, 2007 7:33 PM
> Subject: [GPS_Standard] Frequency control range
>
>
> There's an oscillator on ebay with the spec of...
>
> Frequency Control Range +/- 3 x 10-7 at VC=5 +/- 5v
>
> And I'm unsure what this means.. does it mean centre frequency at 5v with
> an
> adjustment of 0-10v for the frequency control or what?.
>
> FYI the oscillator is a Toyocom TCO-6730. would this device be suitable
for
> a
> VE2ZAZ gps unit or is it not good enough.
>
> thanks, Mike
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