Measurement Computing WBK12A - Manual

Programmable Low-Pass Filter Cards 988396 WBK12A and WBK13A, pg. 1
WBK12A and WBK13A Programmable Low-Pass Filter Cards
Important Notice! WaveBook/516E Users
WBK option cards for WaveBook/516E are installed at the factory per customer order.
Users are not to remove or install cards for these products as the cards are not “plug-and-
play” for these devices and erroneous signal values could result. If you desire to remove
or add a card to WaveBook/516E contact the factory or your service representative.
Important Notice! WaveBook/516, /516A, /512A, and WBK10A Users
With exception of the WBK30 option, WBK option cards for WaveBook/516, /516A,
/512A, and WBK10A are installed at the factory per customer order. Users are not to
remove or install cards for these products [other than WBK30 series cards] as the cards
are not “plug-and-play” for these devices and erroneous signal values could result. If you
desire to remove or add a card to these products, contact the factory or your service
representative.
Description
The WBK12A and WBK13A are 8-channel programmable low-pass filter cards for use with 1-MHz
WaveBook data acquisition systems. These cards install directly into a WaveBook or WBK10A module and
provide programmable low-pass filtering over all channels. Multiple WBK12A and WBK13A cards can be
installed in one system for up to 72 channels. All of the cards’ low-pass filters and cutoff frequencies are
configured via software.
The WBK13A card has the additional capability of sampling all channels at the same time. If more than one
WBK13A card is installed [within one system] all channels will be sampled within 100 ns of each other.
Features of the WBK12A and WBK13A include:
• Anti-Alias 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.
• 500 Khz Low Pass Filter. You can individually configure channels to bypass the programmable filter.
The bypass option results in a 1-pole low-pass filter at approximately 500 kHz.
• Cutoff Frequencies. The WBK12A and WBK13A provide 748 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.
• Simultaneous Sample-and-Hold (SSH) (WBK13 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 a 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.