Measurement Computing WavePort rev.3.0 - Manual (Page 49)

WavePort User’s Manual 09-29-00 Hardware and Operation Reference 4-21
WBK12A and WBK13A - Programmable Low-Pass Filter Cards
The WBK12A and WBK13A are 8-channel programmable low-pass filter cards for use with 1-MHz
WaveBook data acquisition systems, including WavePort. These cards, when ordered as an option, are
factory-installed into WavePort’s WaveBook module, the WBK10A-based Module 1, and/or the WBK10A-
based Module 2, as applicable.
Note that the Module 1 and Module 2 expansions provide programmable low-pass filtering over all
channels. All WBK12A and WBK13A low-pass filters and cutoff frequencies are configured via software.
Note: WBK13A is like the WBK12A, except in that the WBK13A has the additional capability of
simultaneous sampling all of the module’s channels. If multiple WBK13A cards are installed within
one system, all channels will be sampled within 100 ns of each other.
Features of the WBK12A and WBK13A include:
• Low-Pass Filters. Each card provides 8 input channels, arranged in two 4-channel banks; the filter and
cutoff frequency configurations are applied per bank. The cards’ filters can be configured as either an
8-pole elliptic filter with cutoff frequencies of 400 Hz to 100 kHz, or an 8-pole linear-phase filter with
400 Hz to 50 kHz cutoff frequencies.
• Cutoff Frequencies. The WBK12 and WBK13 provide 747 discrete cutoff frequencies that can be
determined exactly by the formula Fc = 300 kHz/N; where the integer N = 3 to 750. Alternatively, you
can configure any channel to bypass the programmable filter entirely, resulting in a 1-pole low-pass
filter at about 500 kHz.
• Programmable-Gain Amplifiers. The cards’ programmable-gain instrumentation amplifiers can be
software selected to various gains on a per channel basis. The gains are set prior to the beginning of an
acquisition sequence and cannot be changed during an acquisition.
Note: WBK12A and WBK13A gain specifications are provided in Chapter 10.
• Simultaneous Sample-and-Hold (SSH) (WBK13A only). In addition to the filtering capability of the
WBK12A, the WBK13A provides per channel SSH. Simultaneous sampling of all channels occurs at
the start of a scan sequence.
When using WaveBook with an SSH channel enabled, the per-channel sample rates are
reduced. The rate reduction is the same as that which would occur if another channel
were added. The per-channel rate (with SSH enabled) is:
1 MHz / (n+1), where n is the number of active channels.
Hardware Setup
Configuration
The WBK12A and WBK13A configurations are controlled by software. No hardware settings are required.
Installation
For the WavePort product lines, WBK12A and WBK13A cards are only to be installed at the factory.
Customer installation or removal of internal WavePort components will void of your product’s warranty.
Software Setup
Reference Note:
For software setup information, refer to the "Software Setup" section in Chapter 2.
For detailed WaveView information, refer to chapter 5.
WBK12A and WBK13A - Specifications
Specifications are provided in Chapter 10.