Description
The TR22 module is an isolated 4 channel digitizer with onboard memory in a PCI form factor. The 4 channels are separately isolated and are sampled simultaneous (not multiplexed) with 14 bit resolution at a speed of max. 2MS/s per channel.
The analog input signals are received by, so-called, instrumentation amplifiers.
The instrumentation amplifiers can have a software selectable gain of 1, 2, 4 or 8.
A buffer placed after this amplifier gives an extra software selectable gain or 1, 0.5, 0.25 or 0.125. Using this PGA functionality a fairly large range of input signal ranges can be mapped on the ADC range efficiently. An analog filter attenuates the higher frequencies present in the input signal.
The filter is built as an active 2nd order Bessel multi feedback filter. The cutoff frequency (-3dB) is at 1 MHz. The samples are recorded in onboard memory. The memory is organized as a 512MB ring buffer (64MS per channel). On every sample clock the A to D converters convert the analog inputs and send the samples over the isolation barrier where they are recorded into the ring buffer.
After the event of a trigger a programmable number of post trigger samples will be stored into this ring buffer before sampling stops. In parallel samples are also available through FIFOs or second ring buffers at sub-sample rates for control applications.
The depth of these FIFOs or ring buffers is software selectable from 1 sample up to 2k samples per channel, up to 4k samples with two channels active, and up to 8k samples with only one channel active. The samples in the 512MB memory and the sub-sample FIFOs or ring buffers can be copied to the PC memory with DMA transfers.
Modules may be connected via the trigger and clock signals, available via the PCI bracket, to increase the number of channels. The modules can also be connected using a flat-cable to distribute clock and/or trigger signals to more TR22 modules within the PC. The plug and play functionality provides easy setup and use.
A software driver for Linux is available.
