M3i enhancement details

These enhancements are included with each card purchase to increase the versatility of the M3i.21xx, M3i.32xx, M3i.41xx and M3i.48xx series boards.
Please contact DataQuest Solutions should you require any further information.

ABA mode

Diagram showing ABA mode operation

ABA mode this allows changing from long-term slow and continuous data logging (through a process of sample decimation), to ultra-fast acquisition on a trigger event. This is handled by the hardware. This is more efficient than having to write code in a post-process program and helps isolate in detail interesting events from reams of data.

In the above diagram the decimated data capture points are shown as blue lines. When a trigger is applied the data is recorded at the full clock speed, here depicted by the green lines in section B. Data is captured for a user definable numbers of times. Pre and post trigger data can be recorded at the full rate if required so that analysis of the signal leading up to the trigger, as well as that following can be performed.

ABA mode significantly reduces stored file sizes. At the sort of rates these ultra high-speed cards can operate, this is a big advantage. The level of decimation can be set in the driver code or the SBench software. The trigger point can be external an TTL pulse, or from the amplitude of the analogue input signal.

Multiple Recording

Image showing signal data transfer following rapidly repeating triggers

Multiple Recording allows the capture of signal data associated with each of several trigger events, without having to restart the hardware. Trigger events which repeat at a very high rate could thus be recognised with this option without risk of any being missed. A trigger re-arm period is required immediately after each capture event, however for the M3i series of boards this is less than 32 samples in length. Should you intentionally wish for an extended delay between trigger arrival and each recording this is software programmable up to 32 Giga samples!

The memory of the board will be divided into several segments of the same size. Each segment will be filled with data when a trigger event occurs.

Multiple Recording may be combined with the Time stamp option to record the start time of a segment.

Time stamp

Image showing each successive time stamp relative to triggers The time stamp function allows recording of trigger moments relative to the start of recording or synchronised to an external radio clock. The time stamp function is designed as an enhancement to the Multiple Recording and the Gated Sampling mode but could also be used without any of these options. The memory of the time stamp function is a FIFO buffer and this allows continuous signal recording with time stamps. Each time stamp is defined by a count of samples and therefore the rate of the A/D converter clock. The relationship between trigger events and the count are set by the modes as described below.

Standard Mode

In standard mode the time stamp counter is set to zero once, with a call to TS_RESET from the users program . After this call the counter counts continuously. The time stamp of all recorded trigger events are referenced on this common zero time. With this mode the exact time difference between different recordings may be calculated.

StartReset Mode

In the StartReset mode a time stamp value calculated from a counter value which increments automatically from zero after the initial start of the card, each trigger that comes along is then time stamped. In Multiple Record mode (described above) many such trigger events can be very close together to capture many individual segments of data in a recording. StartRest mode is very useful here as each segment is individually time stamped. The counter only zeros after the end of the complete recording and the restart of the card.

RefClock Mode

The counter is divided into a HIGH and a LOW part. The HIGH part counts the seconds that have elapse since reset of the whole counter and references the seconds signal of an external radio clock, or any user precise 1Hz signal. The LOW part is reset every second, and defines the position of the trigger event within the current second. The timing signal must be fed into the BASEXIO option as a TTL signal. This mode allows the absolute time of a trigger event to be recorded. Alternatively, the HIGH counter part could also be used to count the number of external triggers

Click for more information plus diagrams on Time stamp: [Time stamp short presentation PDF]

© Dataquest Solutions 14.07.09.
Images courtesy of Spectrum GmbH. Last updated 14.05.18