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122P Charge Amplifier

Users of digital control systems are familiar with the operating restrictions that can be encountered when using the standard 10 mV/g normalized output available from most charge amplifiers. In many cases, the performance of the digital control system is affected significantly by the feedback signal level. For a shock spectrum test, a 10 mV/g acceleration signal may be desirable to accommodate the typically high acceleration levels generated, without exceeding the dynamic range of the digital controller. Conversely for low level tests, optimum control may require a considerably higher acceleration normalization (100 mV/g, 1000 mV/g or greater) in order to meet the loop gain criteria of the digital control system.

These commonly encountered control system requirements can be addressed using the Model 122P Charge Amplifier which provides convenient front panel selection of the acceleration feedback signal sensitivity from .01 to 10 V/g in 1, 3, 10 steps.

The 122P Charge Amplifier utilizes the same basic circuit design as the popular D33 Series Signal Conditioners including extensive use of integrated circuits and rugged, modular construction. Remote charge preamplifiers such as the RCA-2TR can be accommodated by the front panel toggle switch selection, bypassing the internal charge converter. A three-pole low-pass Butterworth filter is provided on a sub-plug-in board within the instrument. A calibration mode allows insertion of an external calibration signal through a rear chassis jack. Up to six units can be rack mounted in a 19 inch rack adapter (Model 80RA).

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  • Convenient selection of feedback control signal sensitivity
  • Front panel switch selects normalized output from 10 mV/g to 10 V/g in 1, 3, 10 steps
  • Allows maximum utilization of digital control system dynamic range
  • Continuous Dial-A-Gain input charge sensitivity adjustment from 1-100 pC/g
  • Operation with remote preamps
  • Plug-in low pass filter