This is where 2 resistor and 2 switch contacts are used per step, making up a unique combination of resistors per step that add up to the impedance of the stepped attenuator you use. Effectively a voltage divider network.
The total series resistance of each two resistor set is equal, so the signal source always sees the same impedance.
Switching type: MBB (Make Before Break)
Number of steps: 48
Attenuation range: -60 dB ... 0 dB
Attenuation per step: steps 1 to 11 - 2dB, 12 to 48 - 1dB
Contact material: Hard gold Polished wiper and contact pins Extremely short signal path
Channel matching: +/-0.1 dB
Resistance: 5K, 10K, 25K, 50K, 100K, 250 kohm
Mechanical life: > 50 000 cycles
CNC machined PA11 aluminium body
Precision ball bearing support
Shaft diameter: 6 mm
Indexing angle: 7,2 deg