[time-nuts] 5>10 doubler

Alexander Pummer alexpcs at ieee.org
Thu Jan 29 20:41:54 EST 2015


And the narrow notch for the harmonic is not required anyway, since the 
fundamental is fare enough, therefore a high Q  LC trap will work 
better, also with the setting of the biasing af the active devices the 
spures could be reduced to [ just observe the output with a spectrum 
analyzer and set the bias of one site to minimum harmonics, there will 
be no common optimum for all harmonics, but a good compromise could be 
achieved ]
73
Alex KJ6UHN
On 1/29/2015 2:16 PM, Richard (Rick) Karlquist wrote:
>
>
> On 1/28/2015 11:28 AM, Charles Steinmetz wrote:
>> Gerhard wrote:
>>
>>> It is a different game when you want to notch away sub/harmonics.
>>
>> One problem with using crystals as traps (notch filters) is that the
>> series resistance of a crystal is several orders of magnitude higher
>> than that of a good series-resonant LC -- generally in the 50-100 ohm
>> range.  So, although the notch is very narrow, it will not be very deep
>> unless it is in a high-impedance circuit.  For example, in a 50 ohm
>
> It is very straightforward to use LC networks to transform the
> impedance of the crystal to a much lower value and get around this
> problem.
>
> Rick Karlquist N6RK
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