# RE: More ISSTC theory stuff

```Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com>

>This structure can be designed exactly to have any bandwidth,
>and any voltage gain or any input resistance, by using the same
>procedures used in the classical design of passive filters.

OK... cool... I agree totally. But what I am trying to find out is the magic
values of bandwidth, voltage gain, and input resistance, that will give
biggest streamer output from a given set of IGBTs, with reasonable tolerance

>It's also possible to make approximate designs by considering the
>network as a series of two L-match impedance matching networks,
>one C-L and the other L-C.

I like this approach. I think that a lot of the design choices we _could_
make in the full bandpass filter network approach are constrained by other
things. For instance the coupling will be limited due to clearances for
primary-secondary flashover, and the voltage gain achievable in the primary
will be limited (I imagine) by such things as flashovers between primary
turns.

With the L-match approach, the problem is reduced to matching the real part
of the streamer load (several hundred kOhm) to the inverter output impedance
(around 1 ohm) The inverter doesn't have an output impedance as such, but
you can express the maximum current you want to draw as an impedance.

(fundamental of inverter output voltage /(peak IGBT current you
want/sqrt(2))

I say fundamental because the inverter output voltage is a square wave but
our analysis will assume a sine wave. The current is a sine wave anyway.

So my plan is to design the secondary according to good HV practice, choose
the highest coupling I can without any risk of flashovers, then choose the
primary L and C by treating it as an L-match. What do you think?

Steve C.

```