Conversion Process
Electronic conversion of continuous analog signals into discrete digital values occurs at fixed intervals to facilitate processor interpretation. Effective adc sampling requires a stable clock source to ensure that the time between measurements remains uniform across the acquisition window. The Nyquist criterion defines the lower boundary for the rate of these measurements, requiring it to exceed twice the highest frequency component present in the input signal.
Aliasing occurs if the frequency content exceeds half the sample rate, resulting in permanent data corruption that no post processing can remove.
Timing Precision
Jitter in the conversion clock introduces uncertainty into the captured waveform. This timing error shifts the moment of measurement, creating a voltage error proportional to the signal rate of change at that specific point. Low jitter oscillators are necessary for high resolution sensing applications.
Signal Integrity
Noise and aperture delay affect the accuracy of the resulting digital stream. The internal circuitry of the converter requires a finite duration to capture the input voltage before the conversion logic begins its work. During this hold time, any fluctuation in the reference voltage or ground plane introduces an offset that shifts the final count.
Shielding and decoupling capacitors minimize these interference effects at the pins.
Sampling Boundary
Input bandwidth of the front end amplifier limits the capture of fast transitions regardless of the rate used for adc sampling. This physical limit ensures that the signal remains within the operational range of the internal track and hold circuit. If the input exceeds this slew rate limit, the output fails to track the analog source accurately.
Proper anti aliasing filtration at the hardware stage prevents out of band noise from folding into the primary measurement spectrum.
