[time-nuts] Buffer / distribution amplifier for TCXO

Henry Hallam henry at pericynthion.org
Wed Aug 4 22:16:34 UTC 2010


On Wed, Aug 4, 2010 at 1:50 PM, Bruce Griffiths
<bruce.griffiths at xtra.co.nz> wrote:

> The TCXO output waveform is presumably a clipped sinewave as required by the
> SE4120L?

I posted the waveform at
http://www.pericynthion.org/stuff/KT3225_500mV_per_div.jpg
Does that count as clipped sine?  If not, it seems to work anyway.

>
> In which case a linear distribution amplifier is probably required.
>
> With only a ~3V supply available, options for the distribution amplifier
> topology are somewhat limited.

I'm making a custom board that will include the TCXO and distribution
amplifier (as well as some digital stuff to allow the 4 receivers to
communicate), so it can have whatever power supplies it needs.

> In principle you could use an emitter follower driving 4 other emitter
> followers with a resistor in series with the emitters of the output devices
> and the AC coupled loads to match the source to the interconnecting cable
> impedance to minimise reflections without requiring excessive dissipation in
> the emitter followers.
> With the low voltage supply available, using an RF choke is series with the
> emitter follower's emitter to ground resistor will also be useful in
> achieving the required dynamic range.

Thanks.


Henry



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