=20
Hi Larry,=20


=20
Hi Larry,=20

    Could you add this Period Extension Article to your list of reference a=
rticles, please ?=20
This serial circuit (as opposed to the parallel circuit described by Robert=
s) was origionally intended to be used with Willmore II seismometers. The p=
eriods of these could be adjusted to between 1 and 3 seconds. However, a re=
sistor needs to be added in series with each of the two R+C feedback networ=
ks to correctly amplify the response above resonance.

    'An Intermediate-Period Field System using a Short-Period Seismometer',=
 by Robert G Daniel, BSSA, Vol 69, No 5, pp 1623-1626, Oct 1979=20

    Regards,=20

    Chris Chapman
=20
















 



Hi Larry, 

 

    Could you add this Period Extension Article to your=
 list of reference articles, please ? 


This serial circuit (as opposed to the parallel circuit described by R=
oberts) was origionally intended to be used with Willmore II seismometers. =
The periods of these could be adjusted to between 1 and 3 seconds. However,=
 a resistor needs to be added in series with each of the two R+C feedb=
ack networks to correctly amplify the response above resonance.

 

    'An Intermediate-Period Field System using a Short-=
Period Seismometer', by Robert G Daniel, BSSA, Vol 69, No 5, pp 1623-1=
626, Oct 1979 

 

    Regards, 

 

    Chris Chapman