[time-nuts] Advice on 10 MHz isolation/distribution (Clay)

Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Feb 12 21:29:03 UTC 2010


life speed wrote:
> I seem to not be accomplishing much isolation from output to input, as well as output to output.  Have I fumbled PSPICE somehow?  For each simulation, Vac was set separately, with V1=0.707V at the input, while V6=0V at the output (sim1).  Then V1=0V, and V6=0.01V (sim2).
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Clay

Your schematic shows no connection from the collector of the npn input 
transistor to the base of the pnp output transistor in any of the stages.
There should be a direct connection from

Q4 collector to Q6 base

Q1 collector to Q3 base

Q7 collector to Q9 base

It usually pays to check the dc voltages and currents before beginning 
an AC or transient analysis to see if they are what you would expect.

Bruce




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