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1.0 Introduction

The TR122 is a high performance two channel transient waveform digitizing instrument

designed in a single slot CPCI module and capable of digitizing to 12 bits at rates up to 200

million samples per second (MS/s) on both channels. Each channel includes an independent

analog front end and analog-to-digital converter providing superior interchannel isolation and

full bandwidth availability on all channels. The TR122 segmented memory architecture and

internal timer allow multiple sequential events to be captured and time stamped without the need

to read data between events. A two million sample static memory is provided for each channel

and is divisible into smaller data segments.

The TR122 analog inputs have nine 1 volt to 500 volt full scale ranges selectable in 1,2,5

steps. A full scale input offset adjustment is also available. The effective sample rate is

adjustable from 1 MS/s to 200 MS/s in eight steps. Each TR122 unit is always an independent

instrument, but can coexist in hardware and software with additional units and other instruments

in the same CPCI system.

The TR122 can respond to trigger events from either channel, from an external trigger

input, or from software. A trigger event stops the continuous recording of a circular buffer of

samples when a specified number of samples after the trigger have been recorded. The number

of samples recorded after the trigger is adjustable. This approach allows the user to select an

appropriate number of pre trigger samples to be left in memory when the record is complete.

A binary status recorded with the data indicates whether each sample was taken before or after

the trigger event. The TR122 software automatically sorts the data to chronological order,

making the intricate details of the records transparent to the user.

The sample memory can be segmented in multiples of 64K samples. A 32-bit (4 billion

count) internal timer is used to record a count with each trigger event which can be used to

determine the relative time of multiple trigger events with microsecond accuracy. These time

stamps are saved in a first-in-first-out (FIFO) memory which can be accessed through the TR122

software to determine how many triggers events are present in the sample memory and when

they occurred with respect to each other.

While the TR122 is not an oscilloscope, the software is designed with much of the look

and feel of an oscilloscope for the benefit of instant user familiarity. The instrument and

connected devices can be configured in an oscilloscope mode and then switched to transient

recorder mode to take advantage of powerful transient recorder features.

Finally, the TR122 software source code is provided as open source. In a world of data

acquisition now muddied by thousands of semi-standard and custom solutions it makes sense

to provide a properly layered design accessible to the user for unique needs. The principles of

the software design are defined in this manual and are intended to allow the advanced user to

peel back the layers and snap in other front end software. Such efforts are always underway

and popular additions will be published on the Data Design website as they become available.

DDC TR122 User Manual

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