2. Raw data

The fast ADC saves raw data from all 10 ADC channels simultaneously. The raw data is saved in the DDR memory available in the SIS8300 board. Some parameters can be tuned by the user to steer the data acquisition, and are presented in the figure below.

The amount of raw data saved with each trigger signal is configured in the Number of raw samples property in the Karabo device. It is possible to delay the raw data acquisition by a fixed number of samples after the trigger signal. This parameter is set by adjusting the Raw Delay property.

It is also possible to define the period of raw data acquisition (save one sample every N samples), which provides a zoom capability when observing raw data signals. As an example, if this register is set to 1, 2 or 3, the device will show an ADC value only every 2, 3 or 4 samples, respectively. The period of raw data acquisition is configured in the parameter Skip Samples. Notice that the parameters delay and period affect all ADCs signals raw data acquisition.

_images/ADC_config.png

Example of an ADC signal and configuration parameters for raw data acquisition. The correspondent Karabo parameters are shown on the right.

The previous parameter affects the raw data acquisition for all channels. Nevertheless, to acquire raw data from a specific channel, the correspondent Enable Raw Data parameter must be set to TRUE in the channel options. Notice that a Signal Description can also be define by the user to easily identify the signal present in that channel.

_images/ADC_chEnable.png

Signal description and Enable Raw Data Karabo parameters for Channel 0.

2.1. ADC Range

The ADC range can be configured to be 1.25, 1.5, 1.75 or 2.0 Voltage peak-to-peak. The setting can be changed when the device is not acquiring (STOP state), there is no need to re-initialize the device.

_images/ADC_vpp.png

ADC range options.

2.2. Time Axis

A time axis property is available for plotting Vector XY Graphs with the Raw data. The values take into account the Number of raw samples, Frequency and Skip Samples values configure in Karabo.

_images/ADC_timeAxis.png

Time Axis property show in Karabo and the Vector XY Graph option in the Widget. After selecting this option, simply drag the Time axis parameter on top of the widget for the X axis to be updated with the time values.

2.3. Virtual Channels

The FastADC includes 5 virtual channels (channel 10 through 14) which can be configured to be the sum or subtraction of two (real) ADC channels. The same features are available in these channels as any other ADC channels (peak integration, bunch pattern peak integration, multibaseline, adc alert, moving average, data voltage conversion, etc.).

_images/addSub.png

Configuration of Channel 10 (Virtual). The channel is configure to be subtraction of the ADC signal in channel 0 and channel 9. The raw data graphs are display on the right.