[time-nuts] reference oscillator input circuit
Bruce Griffiths
bruce.griffiths at xtra.co.nz
Thu Dec 9 20:05:44 UTC 2010
jimlux wrote:
> Javier Herrero wrote:
>> El 09/12/2010 15:21, jimlux escribió:
>>> Javier Herrero wrote:
>>>> Good to know. Now I see what not to use :) I was supposing that the
>>>> hysteresis would not be so high being low voltage signalling, and
>>>> since they are used for low-jitter applications. But really I've
>>>> only used them for their intended main applications :)
>>>
>>>
>>> hysteresis is in the 100mV minimum range, and max peak amplitude is
>>> in the 0.9 to 1 Volt range (they'll have a bias point a bit over a
>>> volt, and a lot of them do not do well at all if you swing close to
>>> the supply rail)
>>>
>>> Maybe with external clamps and over drive it.
>>>
>> Yes, I was thinking in that way. But surely they are better solutions :)
>>
>
> hence my question to the list..
>
> I'm going to gather all the responses and summarize them for the list
> later today.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
Since noise modulation (power supply and device noise) of device
parameters (eg collector base capacitance) can be a significant source
of phase noise adding some emitter degeneration in a long tailed pair
and shunting the collector load resistors with inductors (eg a
transformer winding) should be an effective way of reducing such phase
noise. A capacitor shunting the collector load can also be effective in
reducing the circuit bandwidth closer to the optimum and desensitising
the circuit bandwidth to device parameter variations. However avoiding
high Q parasitic resonances with the output inductors (or transformer)
will be necessary.
Bruce
More information about the time-nuts
mailing list