x10 blocking circuit trade-offs...

["Rick Bolen \(HM\)" <rickbol@xxxxxxxxxxx>]

hello all,

I'm planning to build an x10 [120kHz] filter that I've modelled in PSpice.
One design I found on the internet, and the other I derived by playing
around with available L\C values out of my Mouser catalog.

The design I derived has a wider notch bandwidth than the Inet design (at
any given load_Z). The center frequency of both designs is 118kHz, but with
my derived design I still get -15dB of signal attenuation at 120kHz at 1Kohm
load impedance.

Based on my modelling, the higher the load impedance, the more narrow the
notch bandwidth... and if you're off of the target frequency, you may not
achieve much signal attenuation at all!

So my questions are:

1) what is the range of impedance of a typical house leg circuit at 120kHz?
10ohm? 1kohm? 10kohm? ???

2) would L\C values of 0.01uF and 180uH present any obvious difficulties?

X10 Blocker Circuit:

                180uH           180uH
  BLACK  ----+---))))))---+---))))))---+----  BLACK
             |            |            |
             |    | |     |     | |    |
             -----| |-----+-----| |-----
                  | |     |     | |
                 0.01uF   |     0.01uf
                        -----
                        -----
                          | 1uF
                          |
                        WHITE

Thanks for any advice,

Rick