Data acquisition


ADAQ7769-1 The ADAQ7769-1 builds upon the ADAQ7767- 1 by adding a single-ended programmable gain low noise amplifier. It is still capable of the ±24 V single-ended input range, allowing a DC- coupled IEPE sensor architecture with a more complete solution.


Figure 6. Case isolated accelerometer and an isolation base.


GENERICS AND DISTINCTION There are other generics from the ADAQ7768-1 that use the same integrated ADC, namely the ADAQ7767-1 and the ADAQ7769-1 (Figure 11).


ADAQ7768-1 The ADAQ7768-1 includes a fully differential PGIA. With its high impedance and low input bias current, it connects directly to various sensors. Unlike a conventional voltage feedback amplifier, the integrated PGIA maintains nearly the same bandwidth across all its gain settings— leading to tight device-to-device phase matching regardless of the gain setting.


ADAQ7767-1 The ADAQ7767-1 does not provide an integrated input amplifier—lowering cost and enabling the customer to provide custom input signal conditioning. This device has three input ranges, with a maximum of ±24 V for single-ended inputs, allowing a DC-coupled IEPE sensor architecture and a simpler power solution.


IMPLEMENTING SYNCHRONISATION To obtain the full phase matching performance of these products, it is required that the device follows proper methods of synchronisation.


While there is a generic method of synchronising various products, some devices have their own unique methods that are usually added as a benefit to the overall system. Generally, in many SD ADCs, a SYNC or ¯("SYNC_IN" ) pin is provided to allow a controller to synchronise separate, and usually similar, ADCs with each other. In time-sensitive ADCs, this typically comes with the requirement to have the SYNC pulse in sync with the sha red controller clock (MCLK). Otherwise, the synchronisation trigger of one device may be


Figure 7. Proper grounding: Isolated at the instrumentation, grounded at the accelerometer.


Figure 8. The ADAQ7768-1 functional block diagram. Instrumentation Monthly September 2024


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