Data Acquisition and Validation Flashcards

Which type of transducer converts mechanical strain into an electrical signal for data acquisition?

Answer: Strain gauge

A strain gauge changes electrical resistance proportional to the mechanical deformation applied to it.

What is the primary purpose of anti-aliasing filters in a data acquisition system?

Answer: Remove frequencies above the Nyquist limit before sampling

Anti-aliasing filters attenuate signal components above half the sample rate to prevent aliasing artifacts in the digitized data.

A PCM (Pulse Code Modulation) stream is used in flight test telemetry primarily to:

Answer: Multiplex multiple analog channels into a single digital bit stream

PCM time-division multiplexing encodes multiple channels sequentially into one digital stream for efficient telemetry transmission.

Which validation technique compares measured data against a known reference standard to confirm sensor accuracy?

Answer: Calibration check

Calibration checks verify that sensor output matches a known reference standard within specified accuracy tolerances.

In flight test data acquisition, 'frame synchronization' refers to:

Answer: Identifying the correct starting point of a PCM frame in the bit stream

Frame synchronization detects the unique sync word pattern that marks the beginning of each PCM data frame.

What does 'measurement uncertainty' quantify in a test data context?

Answer: The range within which the true value of a measurement is expected to lie

Measurement uncertainty expresses the statistical range encompassing the true value of a measured quantity at a stated confidence level.

A data acquisition system records a parameter at 200 samples per second. What is the highest frequency that can be accurately captured without aliasing?

Answer: 100 Hz

By the Nyquist theorem, the maximum unambiguous frequency is half the sample rate, so 200 sps captures up to 100 Hz accurately.