Dynamic Signal Analysis Basics (Product Note #001, 32 pages, 1.1 MB)
Describes the basic dynamic signal analysis theory including Fourier Transform, data windowing, linear spectrum, power spectrum, cross spectrum, FRF and coherence, averaging, transient capture and hammer test, overlapping process, SDOF system. Read online here.

Dynamic Signal Analysis Advanced (Product Note #002, 75 pages, 1.85 MB)
Describes the advanced dynamic signal analysis theory including swept sine test with tracking filter, real-time digital filters, octave analysis, sound level meters, order tracking analysis, automated test, shock response spectrum analysis. Read online here.

Define and Measure 160 dBFS Dynamic Range (Product Note #003, 4 pages, 631 KB)
Describes how Crystal Instruments defines the dynamic range of the measurement system and the advanced capabilities of CI products. Read online here.

Industrial Ethernet Switches for Spider Systems (Product Note #005, 2 pages, 291 KB)
Requirements for Industrial Ethernet switches for use with the Spider Vibration controller system. Read online here.

Applying ASAM-ODS in Crystal Instruments Products (Product Note #014, 5 pages, 288.23 KB)
ASAM-ODS is a new industrial standard of data format that are particularly designed for dynamic measurement systems. Read online here.

Anti-Aliasing Filter and Phase Match (Product Note #021, 5 pages, 636 KB)
Crystal Instruments is among the very first companies using sigma-delta converters in early 90s. This paper discussed the sigma-delta converter, anti-aliasing filter and phase match issues in a DSA instrument. Read online here.

What am I going to do with 128 Channels? (Product Note #026, 4 pages, 986 KB)
Applications of a high channel count system are discussed. Read online here.

You have 10 fingers, but that doesn't mean the input range has to be 10 volts! (Product Note #038, 4 pages, 468 KB)
The input channels of the CoCo-80X, Spider-80X and Spider-81 series are very similar in hardware design except the number of channels. Typically, the Spider-80X and the Spider-81 series have 2~16 analog input channels with an isolated BNC connector. The input range is ±20 V with single-ended, differential, IEPE, Charge Mode, and TEDS input type. Read online here.

Patented Technology & Improved Hardware Extends Spider System Dynamic Range to 160 dB (Product Note #053, 2 pages, 378 KB)
Crystal Instruments integrated the advances in electronics into the Spider systems to achieve an additional 10 dB in dynamic range, extending the dynamic range of Spider systems to 160 dBFS. An experimental analysis highlighting this new achievement is published in this article. Read online here.

Running Multiple Large Channel Systems on a Network in Real-time (Product Note #054, 3 pages, 513 KB)
With the implementation of IEEE 1588 Precision Time Protocol (PTP), the same Ethernet connection used for data transmission also provides time clock synchronization. This advanced technology is applied to CI Spider systems, ensuring the possibility of nearly any topology of device and computer connections. Read online here.

Multi-Resolution Spectrum Analysis (Product Note #057, 6 pages, 737 KB)
After over twenty years of research and development, Crystal Instruments successfully introduced and implemented the so-called multi-resolution spectrum analysis in many lines of its products, including CI Random vibration controller, dynamic signal analyzer and modal data acquisition. The multi-resolution spectrum analysis solves the problem mentioned above with enormous benefits. This paper shows how it was realized and example results. Read online here.

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Dynamic Signal Analysis

FRF Limiting Function (Product Note #020, 5 pages, 1.14 MB)
When running a test to measure the FRF of a structure, it may need to check the measured data against a pre-defined limit profile to see whether the measured signal has any point or portion over the limit. This can be done through the so-called FRF Limiting Function. Read online here.

The Modern Maturation of Machinery Monitoring (Product Note #008, 4 pages, 335 KB)
This article discusses the history of machinery monitoring and modern advances today. Read online here.

Wyle Labs Acoustic Testing with the CoCo-80 Acoustic Analyzer (Product Note #011, 3 pages, 410 KB)
Wyle Labs, in California, uses the CoCo for acoustic testing. Read online here.

Vibration Criteria for Facilities with Sensitive Equipment (Product Note #012, 6 pages, 415 KB)
How vibration criteria are used to classify environmental vibration in facilities with sensitive equipment. Read online here.

Audio Functions (Product Note #013, 5 pages, 211.95 KB)
This paper presents the advanced audio functions, including microphone, earphone and voice annotation. Read online here.

Manage Dynamic Signal Analysis Signals using Database (Product Note #016, 11 pages, 1.45 MB)
Describes how thousands of data files are conveniently managed by the EDM database tool. Read online here.

Time Synchronous Average (Product Note #017, 5 pages, 422 KB)
Describes how the time synchronous averaging is applied to the rotating machine analysis. Read online here.

Configurable Signal Analysis (Product Note #018, Paper published in Sound & Vibration Magazine, 3MB)
This feature allows the user to dynamically configure the DSP functions so that data processing flow can be customized from application to application. Read online here.

Consolidation of Dynamic Signal Analyzer and Vibration Data Collector (Presentation, 5MB)
Thoughts behind creating the CoCo-80: integrating a dynamic signal analyzer, a data recorder and a vibration data collector into one package.

An Ear for Gears - Understanding Gearbox Signatures (Product Note #022, 6 pages,1.31 MB)
Speed reducers and other gearboxes are common industrial components. Monitoring their case vibration with accelerometers is an effective means of detecting problems within. Read online here.

Coherence Function - A Brief Review (Product Note #023, 4 pages, 1.18 MB)
A brief review of the Coherence Function and its applications. Read online here.

Data Recording and EDM Post-Analyzer – the Thinking Man’s Alternative (Product Note #024, 3 pages, 4.04 MB)
CI offers EDM Post- Analyzer software, a powerful adjunct to your Spider-based analysis tool kit, allowing you to analyze recordings made using your Spider front-end modules. Read online here.

A New Approach to an Old Sensor – A Spider Tames the Strain Gage (Product Note #025, 4 pages, 2.28 MB)
The Spider-80SG is the first really modern piece of strain gage instrumentation to be commercially developed in decades. Read online here.

Vibration Data Collector: Signal Analysis (Product Note #019, 32 pages, 0.7 MB)
Describes algorithms used in vibration analyzers, including computing the RMS, Peak, Peak-Peak values, FFT spectrum, demodulation spectrum and digital integration for transforming acceleration into velocity or displacement. Read online here.

Remote Condition Monitoring (Product Note #035, 6 pages, 895 KB)
Remote Condition Monitoring (RCM) by Crystal Instruments is designed for the remote monitoring of equipment or structures that are inaccessible to configure within a local network. Read online here.

Spider-80SG System - Breakout Box Terminal Guide (Product Note #036, 4 pages, 663 KB)
The Spider-80SG is designed to be used with strain gages, with the added advantage of utilizing the same intuitive interface from our EDM software platform. The connection to Spider-80SG breakout box is the final piece of the puzzle and it is a lot simpler than it looks. Read online here.

Synchronous Data Acquisition Across A Large Structure or Space (Product Note #037, 2 pages, 530 KB)
Dynamic data acquisition and machine monitoring in a large structure (e.g. airplane) or a large space (e.g. a factory or a plant) often requires data to be acquired synchronously at various locations. Read online here.

Power System Stabilizer Test and Measurement (Product Note #052, 4 pages, 378 KB)
Power system stabilizer testing consists mainly of frequency analysis of power generator systems. The CoCo-80X can be used to evaluate the performance and stability of power generator systems. By determining the phase-frequency characteristics of the excitation control system, the PSS can be tuned to improve small-signal stability. Read online here.

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Vibration Control

What's Required to Bring Vibration Testing In House? (5 MB)
Cover Story for March 2016 Sound and Vibration Magazine

History of Vibration Control Systems (Product Note #004, published in Sound & Vibration Magazine, 0.4MB)
This article discusses the four generations of digital vibration control systems developed by US companies in the past 4 decades. Read online here.

Understanding Random Vibration Testing Signals (Product Note #027, 6 pages, 2.43 MB)
Random vibration testing signals are explained and discussed for the testing professional. Read online here.

Using Fatigue Damage Spectrum with Vibration Control (Product Note #028, 3 pages, 2.10 MB)
Fatigue Damage Spectrum (FDS) allows users to compare the potential damage caused by different Random profiles, swept Sine profiles or a combination of both. Read online here.

Visualizing Mode Shapes with a Stroboscope and Cola Output (Product Note #029, 3 pages, 1.44 MB)
Product application note discussing the use of a stroboscope to visualize mode shapes with Crystal Instruments' Spider systems. Read online here.

Random Control Feature: Non-linear Control (Product Note #030, 3 pages, 756 KB)
Crystal Instruments’ Random Control implements an advanced algorithm which compensates for the effect of non-linearity in the control loop, regardless of whether it is caused by the type of shaker system or the resonance of the device under test. Read online here.

Sine - Resonance Search Track & Dwell Tracking (RSTD) (Product Note #31, 5 pages, 878 KB)
This product note demonstrates the use of Crystal Instruments’ Spider 80X along with EDM (Engineering Data Management) software to determine the resonant frequency of a test object with a very high Q and dwell on the resonant frequency along with tracking the changes in the resonant frequency using the phase value. Read online here.

Random Control Feature: Multi-Resolution Control (Product Note #32, 6 pages, 945 KB)
The Multi-Resolution function perfectly fulfills the requirements of many Random profiles having details in the low frequency range and up to 2kHz. Adequate loop time, spectrum refresh rate, and storage are maintained without using high resolution (large block size) that is not needed in the high frequency. Read online here.

Multiple Shaker Control in EDM Software (Product Note #34, 7 pages, 1043 KB)
Multi-shaker control (MSC) is a unique feature offered by Crystal Instruments EDM Software versions 7.0 and above. The EDM MSC function enables users to view and monitor multiple shaker tests from one PC station. Users can observe testing status, view individual signals from different shaker systems, and send commands to each controller from one centralized application. Read online here.

Center of Operation and Monitoring of 12 or More Shaker Systems with API (Product Note #039, 2 pages, 600 KB)
With these advanced features and robust qualities, Crystal Instruments has been successful in deploying 12 Spider controllers to control 12 shaker systems independently, which are being monitored through one PC from the API. Read online here.

High Resolution Random Control at Low Frequencies (Multi-resolution) (Product Note #041, 3 pages, 588 KB)
The trade-off between control performance at low frequencies and the whole system response is always difficult, but Crystal Instruments has the solution: Multi-Resolution Random Control. Read online here.

Automotive Multi-Sine (Product Note #042, 2 pages, 739 KB)
Multi-Sine is a new type of Sine test which facilitates multiple sine tones sweeping simultaneously at once. In automotive testing, engine mounted components such as fuel lines, turbos, headers, sensors, heatshield… are all subjected to high vibration levels during their operational life cycle. Read online here.

Importance of Spectrum History Sine Signals in a Sine Test (Product Note #044, 3 pages, 366 KB)
Crystal Instruments uses Spectrum history signals, a special type of signals plot to conveniently plot a user defined signal property vs. time or cycles on the X-axis. To ensure the best readability and analysis, the plot is enhanced to accommodate the entire test duration even when the test durations run into several days, weeks or months. With the PC memory as the limitation, test durations of several months or even years can be plotted and viewed simultaneously, thus eliminating any necessity to section the data plot. Read online here.

MIMO Vibration Control vs. Single Shaker Vibration Control (Product Note #046, 3 pages, 561 KB)
With the development of multiple shaker table systems, the availability of Multiple Input Multiple Output (MIMO) controllers and Multiple Input Multiple Output (MIMO) vibration control started emerging a couple of decades ago. Read online here.

Multiple Shaker Table Systems (Product Note #047, 3 pages, 461 KB)
The Multiple Shaker Table System ranges from Multiple Exciter Single Axis (MESA) to Multiple Exciter Multiple Axis (MEMA) with 2 to 6 shakers involved (e.g., three axis translational shaker table, four-poster, 6 DOF Multi Axis Shaker Table (MAST), etc.) Read online here.

Streamlined & Efficient Process of Viewing Signals Acquired in Vibration Tests (Product Note #048, 3 pages, 1.62 MB)
The repetitive manual addition and removal of signals to the display becomes a tedious task. (The purpose of this task is for viewing purposes or for comparisons of the same signals saved in different files.) The Review and Compare mode in EDM streamlines the process, rescuing us from the sheer boredom and inefficiency. Read online here.

Vibration Tests for Seismic Qualification (Product Note #050, 3 pages, 838 KB)
Earthquakes are one of the most destructive forces of nature with the potential to cause devastating life and property losses. In addition to buildings and structures, equipment damaged by earthquakes may directly or indirectly generate hazards for people or the environment. For the safety of employees and the public, equipment designed to perform safety measures (e.g. shut down a reactor) or to function under certain levels of earthquakes for specified periods of time should pass a seismic qualification or a verification of earthquake resistance. Read online here.

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Modal Testing and Analysis

Basics of Structural Vibration Testing and Analysis (Product Note #006, 14 pages, 2.69 MB) 
This application note provides an introduction to the basic concepts of structural vibration. It presents the fundamentals and definitions in terms of the basic concepts. It also discusses practical applications and provides real world examples. Read online here.

Basics of Modal Testing and Analysis (Product Note #007, 12 pages, 4.15 MB) 
This paper discusses the concept of modal analysis, its applications where modal analysis is useful, data acquisition and visualization techniques. Read online here.

Modal Data Acquisition Using the CoCo-80X/90 (Product Note #015, 8 pages, 953.85 KB)
Explains how the CoCo-80X interfaces to the modal analysis software in EDM Modal (Engineering Data Management software) and how the modal data is captured. Read online here.

Modal Testing Preparation Considerations (Product Note #033, 3 pages, 881 KB)
In this technical note, the emphasis is to discuss the necessary technical details regarding the preparation of a successful modal test to acquire a set of FRF signals. Read online here.

Experimental Modal Analysis Overview (Product Note #043, 4 pages, 470 KB)
Experimental Modal Analysis (EMA) has developed into a major technology for the study of structural dynamics in the past several decades. Read online here.

Modal Shaker Testing Using Periodic Random Excitation (Product Note #040, 4 pages, 744 KB)
Modal shaker testing is widely used for experimental modal analysis and to acquire frequency response functions. Either single or multiple modal shakers can be used. The type of excitation used may influence the quality of the testing result and frequency response functions. Read online here.

Applications of Experimental Modal Analysis (Product Note #045, 4 pages, 543 KB)
With modal analysis results, quite a large number of applications are performed for a variety of industries. This note will discuss popular applications that are performed by engineering in industries such as aerospace, automotive, (etc.) Read online here.

Modal Testing Excitation Consideration (Product Note #049, 4 pages, 582 KB)
There are several modal testing methods that consider different types of excitations used. Commonly known methods include Hammer Impact testing and Modal Shaker testing. Please note that Operational Modal Analysis utilizing Ambient Excitation will not be discussed here. Read online here.

Operational Modal Analysis (Product Note #051, 3 pages, 738 KB)
The availability of an operational model opens the way for in-situ model-based diagnosis and damage detection. Hence, a considerable interest exists in extracting valid models directly from the operating data. This develops into the Operational Modal Analysis (OMA). Read online here.

MIMO Stepped Sine Testing Technique (Product Note #055, 3 pages, 622 KB)
The EDM Modal MIMO Stepped Sine Testing option provides multiple Stepped Sine excitations to measure Frequency Response Functions (FRFs). Read online here.

Understanding the Stability Diagram (Product Note #056, 3 pages, 548 KB)
The Stability Diagram is an effective way to display and identify the modes of a structure under test. Nowadays, the Stability Diagram is the standard method for the modal parameter identification stage. Read online here.

Poly-X, the Poly-reference LSCF Implementation and Experiment (Product Note #058, 4 pages, 671 KB)
A poly-reference least-square method for modal parameter identification of a system in frequency-domain is discussed and implemented. It can also be considered as a multi-reference frequency-domain implementation of the recognized time-domain based Least-Squares Complex Exponential (LSCE) estimator. Read online here.

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