DBK4

2-Channel Dynamic Signal-Input CardFeatures• Provides two dynamic analog inputs• Offers a per-channel programmablegain amplifier for ±50 mV, ±500 mV,or ±5V FS input• Includes a built-in current source for
IEPE transducer biasing• Offers per-channel anti-aliasing filterswith eight software programmable
cutoff frequencies from 141.6 Hz to18 kHz• Provides per-channel simultaneous
sample & hold• Accommodates either AC or DC coupled signals• Includes BNC connectors and footprints for two user-provided ­Microdot™
connectors• Both dynamic analog inputs sampled
within 50 ns of each other
The 2-channel DBK4 dynamic signal-input
card enables IOtech’s data ­acquisition systems to accommodate inputs from piezoelectric transducers, such as accelerometersor microphones, as well as from various
other dynamic signal sources. Each DBK4
card is equipped with two BNC connectors and footprints for two user-installed
Microdot™ connectors, ­permitting it toeasily accommodate most transducer connections. Up to 128 cards can be attached
to one system for a total of 256 dynamic
signal inputs.
Architecture. The DBK4 provides per-­channel, constant current source outputs,
programmable gain amplifiers, programmable anti-aliasing filters, and ­simultaneous
sample and hold amplifiers.
Current Source. The DBK4’s constantcurrent source can be jumper-set to either
2 or 4 mA. The card can also be configured to disable the current source via
jumpers, enabling its use in applications
that require only programmable gain,­programmable filtering, and simultaneous
sample and hold.

Measurement Computing

The 2-channel DBK4 provides systems with the ability to accept dynamic signal sources

DBK4 Dynamic Signal-Input Card Block Diagram

BNC
Ch. 0

Coupling
network

PGA

ProgrammablefilterSS&H

Buffer

+15V–15V+5V

Microdot
Current
source 102 mA

Reference

Microdot

4 mA

Current
source 2

Programmableclock6Microcontroller

15Channel
selector
Coupling
network

Ch. 1

P1

PGA

ProgrammablefilterSS&H

Buffer

7

Control Bus

BNC

Programmable Gain. The DBK4’s programmable gain amplifier accepts full-scale inputs of ±50 mV, ±500 mV, or ±5V. Because
its gain is software-selectable per channel,
the card can accommodate a different gainon each channel.­(508) 946-5100

1Anti-Aliasing Filter. The card’s programmable low-pass Butterworth filter can besoftware set to one of eight different cutoff
frequencies, from 141.6 Hz to 18 kHz, ona per-channel basis. The anti-aliasing filter
can also be bypassed, expanding the card’s
bandwidth up to 40 kHz per channel.

info@mccdaq.com

mccdaq.com

DBK4

Specifications & Ordering Information
Sample and Hold Amplifier*. The card’s
sample and hold amplifier allows all channels in a system (up to 256) to be sampled
within 50 ns of one another.
Power Note: Depending upon system
configuration, a system may require
supplemental power to run DBK expansion
options. For complete analysis, see system
power requirements worksheet online tocalculate your specific needs.

Specifications

Phase Matching Frequency Cutoff

Channels: 2Connectors: DB37 male, mates with P1**; 1 BNC
per channel and footprints for one user-provided
Microdot™ connector per channel
Current Source
Output Impedance: >1.4 MOhm
Compliance: 27V
Current Levels: 2 and 4 mA (jumper selectable)
Broadband Noise: 0.3 µA RMS (BW=100 kHz)
Input Impedance: 150 kOhm
Input Ranges: ±50 mV, ±500 mV, and ±5V FS; additional
full scale ranges are available when combined with
the LogBook’s, DaqBook’s, or DaqBoard’s on-board
programmable A/D ranges
Coupling: AC and DC
AC High-Pass Filters: Per-channel, 1‑pole HPF with
10-Hz or 0.1-Hz cutoff, selectable via jumper
Input Signal/Noise: >96 dB (BW=100 kHz)
Amplitude Accuracy: ±0.5 dB passband center
Low-Pass Filter: Software selectable, 12-pole Butterworth filter, with cutoff frequencies of 18 kHz, 9 kHz,
4.5 kHz, 2.25 kHz, 1.125 kHz, 562.5 Hz, 281.2 Hz, and141.6 Hz; each channel can be configured for a­different cutoff frequency
Distortion (Typical)
Bypass Mode: Jumpers JP7 and JP8 in the 1-2
position disabling the programmable low-pass filter			 @ 100 Hz -81 dB		 @ 1 kHz -82 dB			 @ 5 kHz -81 dB
Filter Mode†: Jumpers JP7 and JP8 in the 2-3
position enabling the programmable low-passfilter, with the following cutoff frequencies
selected via software			 4.5 kHz Cutoff Frequency:		 @ 100 Hz -79 dB		 @ 1 kHz -75 dB			 18 kHz Cutoff Frequency:		 @ 100 Hz -68 dB		 @ 1 kHz -68 dB		 @ 5 kHz -58 dB
Flatness DC-80% Fc: ±0.2 dB
Phase Matching DC-80% Fc: See accompanying chart
Accuracy Passband Center: ±0.5 dB
Power Consumption:  2750 mW

Corner Frequency

Typical Phase Match

18 kHz9 kHz
4.5 kHz2.25 kHz
1.125 Hz563 Hz281 Hz141 Hz

±3.0°
±1.3°
±0.7°
±0.6°
±0.5°
±0.5°
±0.5°
±0.5°

Ordering Information
Description
2-channel dynamic signal-input card

Part No.
DBK4Cables
For use with DBK10, use CA-37-x ribbon cable, orcontact factory of additional cabling options
For use with DBK60 or LogBook/360, no cable isrequired (except from DBK60 or LogBook/360 tothe A/D mainframe)
For use with no enclosure, use CA-37-x where x is thenumber of DBK devices attached
For use with DaqLab Series (internal slots), use
CA-255-2T with one board, or CA-37-2 for use with
two DBK cards (or contact factory for ­additionalcabling options)

Product Compatibility✔ LogBook✔ DaqBook✔ DaqLab✔ DaqScan✔ DaqBoard/2000 Series* In systems incorporating DBK products with SSH, the per-channel rate is [Maximum A/D rate/(n + 1)], where
n=number of channels.
** Attachment to the DaqBoard/2000 Series requires a DBK200, DBK202, DBK203A, DBK209, DBK213, orDBK214† Filter mode measurements were taken at the +5V range with the software enabled switched capacitor clockand excitation

Measurement Computing(508) 946-5100

2

info@mccdaq.com

mccdaq.com