User`s guide

305
Chapter 7 Tutorial
Low-Level Signal Multiplexing and Switching
4
7
The 34901A and 34902A multiplexers have an additional relay, called a
bank switch or tree switch, which helps reduce channel-to- channel noise
(C
adj
). The multiplexer channels are divided into two banks. The bank
switch isolates one bank of channels from the other, effectively removing
any parallel adjacent capacitance from the isolated bank. During a scan,
the instrument automatically controls the bank switches.
If you are not using all of the channels on the multiplexer, divide the
input signals equally between Bank 1 and Bank 2. For example, if you
are multiplexing eight channels using the 16-channel multiplexer, use
four channels in the lower bank and four channels in the upper bank. For
even better noise immunity, leave one unused, grounded channel
between each input channel.
Module Bank 1 Bank 2
34901A Channels 1 through 10 Channels 11 through 20
34902 Channels 1 through 8 Channels 9 through 16
34908A Channels 1 through 20 Channels 21 through 40
Source
Source
Source
Bank 1
Bank 2
Channel
DMM
Bank Switch
Bank Switch
C
adj
C
adj
Source
Switch
Channel
Switch
34970A Refresh UG.book Page 305 Wednesday, February 17, 2010 12:34 PM