Time waveform replication testing solutions

In addition to the three major test types of Sine, Random and Shock, Crystal Instruments also offers Time Waveform replication, or TWR. This is a method to exactly recreate, or replicate, a vibration in its time waveform format on a shaker system.

 

About time waveform replication testing

Data recording for dynamic signals 
While many manufacturers provide long term data recording functions on various hardware platforms, it is difficult to find a good data recording instrument that meets following requirements:

  • For dynamic data acquisition and data recording, the samples of all input channels must be accurately synchronized. The time synchronization accuracy must be better than 100ns (or 1 degree phase match at 20kHz).
  • The sampling rate of each channel for data recording functions must be as high as 100kHz to cover the useful frequency range of sound and vibration applications.
  • The data storage media for data recording must be reliable, anti-shock, and vibration. Regular hard-drives using electrical spindles cannot be used for this application.
  • Data storage in data recording devices must have a minimum of a few hundred gigabytes
  • Data must be stored without losing dynamic range. A 32bit floating point format is preferred.
  • Some customers may require a portable data recording solution
  • Some customer may require hundreds of input channels for their data recording needs.
  • The data recording module must have input channels that accommodate various vibration and acoustic sensors.
  • The data recording action is triggered by various events, such as level or edge trigger, timer, alarm or abort limiting events etc.
  • Post processing software for data recording must be capable of handling very large files efficiently to playback, process and export the data files.

Crystal Instruments provides two solutions for long term data recording that meets all the requirements described above. 

With various excitations, the characteristics of the UUT system are measured experimentally. These characteristics include:

Handheld data recording solution 
The first data recording solution is the CoCo-80 and CoCo-90 for portable applications. The long time waveform from each channel simultaneously records into the internal flash memory or external SD card. A dedicated REC hard button equipped with the handheld, portable data recording instruments make recording as easy as pushing a button.

Data recording for high channel count system 
The second data recording solution is the Spider-NAS. It is the ideal data recording solution for high channel count data acquisition and data recording. 

The Spider-NAS (Network Attached Storage) is a dedicated data recording storage device that works with front-end modules from Crystal Instruments, including the Spider-80X, Spider-81, and Spider-DAQ. Eight high-speed data buses interface directly with each Spider front-end module. An Ethernet port is used to configure and control the Spider-NAS during data recording operations.