$ perl attenuator_pad.pl

********************************************************************************
10dB Attenuator terminated w/ 50 ohms
********************************************************************************
10dB Pad
   N: in_neg(1) in_pos(2) out_neg(3) out_pos(4)
   (1 3 0.05), (2 1 100), (2 4 75), (4 3 100)

50 ohm terminator
   N: in_neg(5) in_pos(6)
   (6 5 50)

10dB Pad + terminator
   N: in_neg(1) in_pos(2)
   (1 3 0.05), (2 1 100), (2 4 75), (4 3 50), (4 3 100)

Simplified network
   N: in_neg(1) in_pos(2)
   (1 2 52)


********************************************************************************
Two pads cascaded and terminated
********************************************************************************
PAD 10dB
   N: in_neg(1) in_pos(2) out_neg(3) out_pos(4)
   (1 3 0.05), (2 1 100), (2 4 75), (4 3 100)

PAD 20dB
   N: in_neg(5) in_pos(6) out_neg(7) out_pos(8)
   (5 7 0.05), (6 5 68), (6 8 270), (8 7 68)

TERM 50ohm
   N: in_neg(9) in_pos(10)
   (10 9 50)

PAD 20dB + TERM 50ohm
   N: in_neg(5) in_pos(6)
   (5 7 0.05), (6 5 68), (6 8 270), (8 7 50), (8 7 68)

PAD 10dB + PAD 20dB + TERM 50ohm
   N: in_neg(1) in_pos(2)
   (1 3 0.05), (2 1 100), (2 4 75), (3 7 0.05), (4 3 68), (4 3 100), (4 8 270), (8 7 50), (8 7 68)

RESULT!
   N: in_neg(1) in_pos(2)
   (1 2 52.5)