Term Definition
AC-coupled

Means that the frontend of the digitizer will block DC components of signals, while allowing AC signals through.

ADQAPI

Application Programming Interface for SP Devices digitizers - It is a set of functions exported to use the digitizers.

Bandwidth

The frequency range where the measured response is above a certain limit (for instance -3dB bandwidth describes the frequency range where the measured response is over -3dB).

Continuous wave

See RF signal.

CW

See RF signal.

DC-coupled

Means that the frontend of the digitizer will allow both DC and AC components of signals through.

Decimation

Decimation is a two-step sample rate reduction method where the data is first filtered, then samples are discarded.  The filter operation reduces the bandwidth and increase the SNR. For high order decimation, the SNR is very high and the data word has to be increased from 16 bits to 32 bits so that the quantization noise does not limit SNR. The sample skip operation reduce the data rate by discarding samples. (Notice the difference to sample skip, where samples are discarded without filtering.)

Digital Down Converter

A DDC combines a complex mixer with a decimation filter to select a specific RF band and reduce the data rate to suit the bandwidth of that RF band.

Interleaving Technology

The interleaving technology gives a high signal bandwidth coverage. The interleaving technology is managed by SP Devices'; proprietary technology ADX, which removes typical interleaving artifacts and enables the unique combination of bandwidth and dynamic range which is characterizing digitizer solutions from SP Devices.

Pulse signal

The typical property of a pulse shaped signal is that it has a short existence in time, only a few samples. This implies that the pulse has a wide spectral content. A typical signal consists of a series of pulses that are recorded one by one or all as a bunch. Important digitizer parameters for pulse measure are high bandwidth, time-stamp and high dynamic range. 

Quantization noise

Quantization noise is the effect of representing an analog continuous signal with a discrete number (digital signal). The rounding error is referred to as quantization noise. The quantization noise is nearly random (at least for high resolution digitizers) and is treated as a noise source. 

Record

Record is a set of consecutive samples. These samples are captured at a trigger event

RF Signal

The typical properties of an RF signal is that it has a limited spread in frequency, that is it is limited to a certain frequency band. This implies that the RF signal has a long distribution in time. A typical signal consists of several tones (frequency bands) that are recorded one by one or all as a bunch. At the input of the digitizer is a signal with very high bandwidth to cover the frequency up to RF frequency. The RF signal of interest has often a limited bandwidth which means that a DDC can be used for reducing the data rate to the signal band of interest.  Important digitizer parameters for RF measure are high bandwidth, high dynamic range, DDC-firmware.

Sample frequency

The frequency at which the device is acquiring samples - the frequency of the clock used to sample data. Measured in Hz (kHz, MHz, GHz).

Sample skip

Sample skip means that samples are discarded to lower the effective sample rate. (Notice the difference to decimation, where the signal filtered before samples are discarded).

Sampling Rate

An A/D converter converts an analog signal into a stream of digital numbers, each representing the analog signal's amplitude at a moment in time. Each number is called a "sample." The number sample per second is called the sampling rate, measured in samples per second.

SDK

Is the distributable containing API, Documentation, Reference Guide, Programming Examples, basic oscilloscope application ADCaptureLab (Windows only). This is what is needed to use and program the digitizers in any language.

Spurious-Free Dynamic Range

SFDR is an important measure which characterizes the dynamic performance of ADCs and DACs. It specifies the ratio between the amplitude of the fundamental and the strongest spurious signal. SFDR together with ENOB give a good understanding of the dynamic performance of SP Devices high-performance digitizers.

Sustained data rate

The sustained data rate means the average transfer rate from the digitizer to the host PC. The sustained data rate measures the actual rate of real data and is NOT including headers and channel coding. The ADQ can maintain the sustained data rate continuously and uninterrupted. (Note that the PC must have the capacity to receive the data at the specified rate.)

Time-stamp

Time-stamp is a real-time measure of the time of a trigger event. The time-stamp is available in the record header. Time-stamp start point is determined by the user through a reset command. The pace of the time-stamp counter is set by the clock of the digitizer. 

Trigger Event

Trigger event is an external signal that activates the data acquisition. This can be a dedicated trigger signal on the trigger input connector, a software command, or an event on the analog signal. 

Waveform

See Record.

Waveform Averaging

The waveform averaging allows for significant data reduction meaning that a USB 3.0 interface is sufficient in many situations. This means that “any” PC can be used as host. This opens for an optimal systems solution. The USB 3.0 also allows placing the ADQ14 close to the experiment and thereby minimizing the cable length from the detector to the ADQ14. This is crucial for limiting reflections. Even more isolation can be achieved with the 10 GbE interface which also add electrical isolation between the ADQ14 and the PC. This is an efficient solution for ground current issues.