The following is a note on terminology used in this calculator.

Decibel (dB): A unit of amplitude defined logarithmically. For voltage values, dB is given as 20log(VA/VB); for power values, it is given as 10log(PA/PB). dBc is the dB value relative to a carrier signal; dBm is the dB value relative to 1mW. For dBm, the load resistance in the specification must be known (e.g., 1mW delivered to 50Ω) to determine the equivalent voltage or current value.

Effective Number of Bits (ENOB): A measure of the number of bits of an analog-to-digital converter (ADC) relative to the input frequency fIN. As fIN increases, the overall noise (especially the distortion components) will increase, thus degrading ENOB and SINAD performance. Also see: Signal-to-Noise + Distortion Ratio (SINAD).

Resolution: When an analog signal is quantized, it is represented by a finite number of discrete voltage levels. Resolution is the number of discrete levels used to represent the signal. To recover the analog signal more accurately, the resolution must be increased. Resolution is usually defined as the number of bits. Converting with higher resolution reduces quantization noise.

RMS: See note on root mean square (RMS).

Root Mean Square (RMS): Indicates the effective value or effective DC value of an AC signal. For a sine wave, RMS is 0.707 times the peak value, or 0.354 times the peak-to-peak value.

SFDR: See the note on Spurious Free Dynamic Range (SFDR).

Signal-to-Noise + Distortion Ratio (SINAD): The ratio of the RMS value of a sine wave, fIN (the input sine wave for an ADC, or the reconstructed output sine wave for an ADC/DAC) to the RMS value of the converter noise, including harmonic content, from DC to the Nyquist frequency. Typical values are expressed in decibels, see also the notes on Root Mean Square (RMS) and Total Harmonic Distortion.

Signal-to-Noise Ratio (SNR): The ratio of the RMS value of a sine wave, fIN (input sine wave for ADCs, reconstructed output sine wave for ADCs/DACs) to the RMS value of the converter noise, excluding dc noise and harmonic distortion, from dc to the Nyquist frequency. Typical values are expressed in decibels, see also the note about RMS.

Ideally, the theoretical minimum conversion noise includes only quantization noise and can be calculated directly from the data conversion resolution: (N): SNR = (6.02N +1.76)dB

Spurious Free Dynamic Range (SFDR): The ratio of the RMS value of the sine wave fIN (input sine wave for ADCs and reconstructed output sine wave for ADCs/DACs) to the RMS value of the spurious signal observed in the frequency domain. The typical value is expressed in decibels. SFDR is very important in some communication systems that require maximum converter dynamic range.

Total Harmonic Distortion (THD): The ratio of the RMS value of the distortion appearing at integer multiples of the input (or output for DACs) frequency (harmonics) to the RMS value of the input (or output) sine wave. Only harmonics within the Nyquist limit are included in the measurement. The typical value is expressed in decibels.