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Product Notes | Spectrum

General Introduction to Waveform Digitizers

This article provides general information about digitizers. The article explains in detail different features and the difference between digitizers and digital oscilloscopes. In addition this article provides a glossary of common digitizer specifications and terms.  Introduction

Advantages of High Resolution at High Bandwidth Digitizers

Two of the key specifications of digitizers are bandwidth and amplitude resolution. These specifications are not independent - with increasing resolution available with decreasing bandwidth. Users must make a tradeoff in selecting a digitizer to meet their measurement needs. This article discusses the advantages and limitations of high resolution in high bandwidth digitizers. Where high resolution is greater than 12 bits and high bandwidth is greater than 20 MHz.   High Resolution and Bandwidth

Using Modular Digitizer Acquisition Modes

Modular digitizers offer many acquisition features matched to the primary application of acquiring multiple channels of input data and transferring that data at high rates to analysis computers. They also offer multiple acquisition modes that are intended to use on-board memory efficiently and decrease the dead time between acquisitions. This is especially true with signals that occur at low duty cycles in such applications as echo ranging (including radar, sonar, lidar, and ultrasound), and transient data collection applications (such as time of flight spectrometry and other stimulus-response based analysis).   Acquisition Modes

Digitizer Front-End Signal Conditioning

Modular digitizers and similar measuring instruments need to match a wide variety of signal characteristics to the fixed input range of the internal analog to digital converter (ADC). Digitizer front ends must also minimize loading of the device being tested and provide appropriate coupling. Additionally, filtering may be needed to reduce the impact of broadband noise. All of these features are provided by the instruments ‘front end’ which includes all the circuitry between the input and the ADC.   Digitizer Front-End

Trigger and Synchronization

Digitizers are used to convert electrical signals into a series of measurements that are then output as a numerical array of amplitude values versus time. To make this information useful the time information is typically related to a specific reference point which is most commonly the trigger position. The trigger point can be something that occurs within the measured signal or it can be from other external sources. The function of triggering is to link the time measurements to a specific known point in time.   Trigger and Synchronization

Probes and Sensors

Probes convert signal levels, change impedance levels, or offer convenient connection methods. Sensors or transducers convert physical phenomena to electrical signals. Examples include current probes, accelerometers, and photomultipliers. Both types of input devices are supported by Spectrum digitizers. This application note deals with using both probes and sensors with Spectrum modular digitizers.   Read More

Common Digitizer Setup Problems to avoid

When it comes to making measurements with modular digitizers it is important to be aware of some common setup problems that will result in bad data and lost time. Among the setup issues that can arise are aliasing, insufficient amplitude resolution, incorrect amplitude range selection, improper coupling, improper termination, poor trigger setup, and excessive noise and spurious pickup. This article will look into each of these issues and provide insight into how to prevent these errors from occurring.   Read More

Software Support

Although modular digitizers can be considered computer hardware they require suitable firmware and software in order to be integrated into the host computer system. Digitizers use embedded software and require device drivers, maintenance software and operational applications to control, view and transfer the digitizer’s data. Software can be supplied or it can be custom developed, this application note provides an overview of the software required to support modular digitizers.   Software

LXI Digitizer

Have you ever been challenged to take multiple measurements in a short period of time? In this article we will discuss the key features of the digitizerNETBOX, an LXI digitizer instrument, and demonstrate how it can make real world measurements on an air compressor. We’ll show how to install and connect the instrument and then set up the measurement with the included software - all within a few minutes.   LXI Digitizer

Operating Software SBench 6

Modular digitizers are typically small compact devices that allow the capture and conversion of analog electronic signals into digital data. The data can then be stored in on-board memory or transferred to a PC. As digitizers are ‘blind’ instruments they do not normally have an integral display to view, measure or analyze the data they collect. Instead, these functions are usually performed by a PC. Thanks to today’s technology PC’s offer massive amounts of processing power, large displays and huge storage capabilities. Notebook PC’s can even be used to provide easy portability in remote or mobile applications.   Operating Software SBench 6

An Introduction to Modular Arbitrary Function Generators

Electronic test and measurements equipment can be classified into two major categories; measurement instruments and signal sources. Instruments such as digital multi-meters, digitizers, oscilloscopes, spectrum analyzers, and logic analyzers measure electrical characteristics of an input signal, most typically electrical potential difference or voltage. Signal sources are required to provide signals to be used as a test stimulus.   AWG Introduction

Using Arbitrary Waveform Generator Operating Modes Effectively

One of the great powers of Arbitrary Waveform Generators (AWG’s) is that they can generate an almost infinite number of waveform shapes. The AWG’s operating mode controls the timing of how these waveforms are output.   Using AWG Operating Modes

Creating AWG Waveforms in SBench 6 using Equations

Arbitrary waveform generators (AWG's) are among the most powerful signal sources available for testing. They offer an extensive range of waveshapes which can be created and selected to rapidly provide a broad range of test events. This application note provides an overview of the rules for waveform creation along with a series of detailed examples. Let’s start with an overview of the waveform creation elements available in SBench 6.   AWG Waveform Generation with SBench 6

Creating, Capturing and Transferring Waveforms for Arbitrary Waveform Generators Using SBench 6

The Arbitrary Waveform Generator (AWG) is a powerful and flexible signal generator capable of outputting any wave shape within the bandwidth of the generator. Once you have the AWG you will need to populate it with waveforms. The cost of creating, capturing, modifying, and transferring test waveforms can easily match the cost of the generator. This application note is intended to make the process easier by providing examples of creating, capturing, modifying, and transferring waveforms to your AWG. We will cover function generator mode, waveform creation using equations, transferring acquired waveforms from digitizers, oscilloscopes, and third party math software like MATLAB.   Creating, Capturing and Transfering AWG Waveforms

Using software based fast block averaging

The block, or segmented memory, averaging mode is used with Digitizers for different applications where incoherent noise needs to be removed from a signal. Independent of the manufacturer of the digitizer all FPGA based hardware implementations of the block averaging mode limit the maximum size of the segment to be averaged. The limit depends on the capacity of the FPGA and usually ranges from 32k up to 500k samples.   Software Based Block Averaging