The cheap probes probably lack the resistive inner conductor in their
interconnecting coaxial cables.
This results in a poorly damped transient response.
Bruce
Eric Garner wrote:
I too, fell for the siren song of cheap Chinese probes. 2 years after
I bought 4 of them, only one has not failed. However, my 1980's
vintage probes from Tek still work dandily.
On Thu, Mar 17, 2011 at 12:47 PM, beale<be...@bealecorner.com> wrote:
Yes, I am controlling the OCXO frequency with a voltage input (center tap of
10k trimpot from +5V to ground). I hooked up my custom 26 MHz PIC divider* and
was able to trim the OCXO to match the output of my GPS 1pps signal to better
than 1E-9 (at least for short periods of time).
These parts draw about 60 mA at +5V in operation in a 23 C ambient environment,
after a brief one-time warmup pulse of about 200 mA. The can gets a bit warm if
left open. I taped a small thermistor against the case, and made a little
styrofoam box to nest snugly over it and measured the can case temp to reach
about 50 C when thus insulated.
I am accumulating some performance data on the two units I have and can post it
online if anyone is interested. (actually, I was thinking of buying a bunch
more before posting the data, because the price seems too good to be true).
* http://www.bealecorner.org/best/measure/time/source/
Scott Newell wrote:
That's a great price for any OCXO. Do they have EFC? (I can't tell from the
part number in the auction photo.)
At 01:41 PM 3/17/2011, beale wrote:
output of a 26 MHz Pletronics OCXO in a 14DIP can (by the way these go for
$2 online, the cheapest OCXO I've seen).
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