Manual ibaPADU-8-M
18
Issue 1.9
9
Settings of the Device
Each ibaPADU-8-M is programmable. A single, common sampling rate for all channels
may be set.
9.1
Sampling Rate
The sampling rate can be programmed via the ibaFOB interface in steps of 50 nano-
seconds from 40
s (25 kHz) to 2 ms (500 Hz). The chosen sample rate is then com-
mon for all channels, analog and digital. Each channel has an individual ADC circuit to
ensure very accurate phase matching between channels.
9.2
Input Gain
Note
No input gain may be changed with program setting. The gain factor is fixed to 1. The
response on a parameter request is 0 = 0 dB!
9.3
Low Pass Filter
Note
The ibaPADU-8-M only has a fixed input low pass filter for each channel. No program-
mable setting are to be made for this. The response on a parameter request is
f
tp
= 0 Hz (no filter).
9.4
Input Impedance
The input impedance changes with frequency!
Standard values for 6 dB low pass
Ri
ON
= 100 kOhm @100 Hz; 10 kOhm @ 5 kHz
Ri
OFF
= 50 kOhm
Note
At corner frequencies < 1000 Hz, reflected frequencies above 50x the corner frequency
are possible.
Example 1: f
c
= 100 Hz
reflected frequency band starts at 50 x 100 Hz = 5000 Hz. A signal frequency of
5100 Hz would be noticeable at 100 Hz.
Example 2: f
c
= 1000 Hz
reflected frequency band starts at 50 x 1000 Hz = 50000 Hz. A signal frequency of
51000 Hz would be dampened 6dB by the static low-pass filter. This signal would be
noticeable for signal strengths above 20 dB.
If a device for low-frequency applications should be required, iba can supply a variant
of this device for sampling at 1 kHz or less, with a static low-pass filter. Please contact
iba for further details.