Hi!
I have a HP G-69B-2 Z-235 Crystal Oven 100 kHz lying around. I'm considering
heating it up and run it (just for fun). Operating temperature is 65 C.
Anyone care to share any information on this device? I have no clue which box
it ever was in or anything. Also, thoughts of suitable oscillator setups?
I should probably have a run-by the network analyzer.
Cheers,
Magnus
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Magnus
Typical face shear 100kHz crystals have a maximum drive level of 2
milliwatts and a max ESR of 5kohms.
This implies a maximum crystal drive current of 630uA rms.
You may wish to restrict the crystal dissipation to less than 100uW or
less corresponding to a crystal current of 140uA rms or less for a
crystal ESR of 5kohm.
At such low frequencies an opamp with a shunt feedback resistor becomes
a viable option for the buffer amplifier.
Just connect the one end of the crystal directly to the opamp summing
junction.
If an OPA134 opamp with a 140 uA crystal current and a 14K shunt
feedback resistor were employed to drive 2V rms into a 1K load the
distortion products will be 80dB below the carrier and the output will
have relatively low phase noise. An additional buffer stage is required
to drive a 50 ohm load.
Bruce
Magnus Danielson wrote:
> Hi!
>
> I have a HP G-69B-2 Z-235 Crystal Oven 100 kHz lying around. I'm considering
> heating it up and run it (just for fun). Operating temperature is 65 C.
>
> Anyone care to share any information on this device? I have no clue which box
> it ever was in or anything. Also, thoughts of suitable oscillator setups?
>
> I should probably have a run-by the network analyzer.
>
> Cheers,
> Magnus
>
> _______________________________________________
> time-nuts mailing list
> time-nuts@febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>
>
Magnus
Typical face shear 100kHz crystals have a maximum drive level of 2
milliwatts and a max ESR of 5kohms.
This implies a maximum crystal drive current of 630uA rms.
You may wish to restrict the crystal dissipation to less than 100uW or
less corresponding to a crystal current of 140uA rms or less for a
crystal ESR of 5kohm.
At such low frequencies an opamp with a shunt feedback resistor becomes
a viable option for the buffer amplifier.
Just connect the one end of the crystal directly to the opamp summing
junction.
If an OPA134 opamp with a 140 uA crystal current and a 14K shunt
feedback resistor were employed to drive 2V rms into a 1K load the
distortion products will be 80dB below the carrier and the output will
have relatively low phase noise. An additional buffer stage is required
to drive a 50 ohm load.
Bruce
