M1AFS250-FGG256I Actel Corporation, M1AFS250-FGG256I Datasheet - Page 131

• Manufacturer Part Number: M1AFS250-FGG256I
• Description: Actel Fusion Family Of Mixed Signal Fpgas
• Manufacturer: Actel Corporation

Figure 2-90 • Offset Error
ADC resolution is the number of bits used to represent an analog input signal. To more accurately
replicate the analog signal, resolution needs to be increased.
Sampling rate or sample frequency, specified in samples per second (sps), is the rate at which an ADC
acquires (samples) the analog input.
SNR is the ratio of the amplitude of the desired signal to the amplitude of the noise signals at a given
point in time. For a waveform perfectly reconstructed from digital samples, the theoretical maximum SNR
(EQ
error). The ideal, theoretical minimum ADC noise is caused by quantization error only and results directly
from the ADC’s resolution (N bits):
SINAD is the ratio of the rms amplitude to the mean value of the root-sum-square of the all other spectral
components, including harmonics, but excluding DC. SINAD is a good indication of the overall dynamic
performance of an ADC because it includes all components which make up noise and distortion.
THD measures the distortion content of a signal, and is specified in decibels relative to the carrier (dBc).
THD is the ratio of the RMS sum of the selected harmonics of the input signal to the fundamental itself.
Only harmonics within the Nyquist limit are included in the measurement.
Resolution
Sampling Rate
SNR – Signal-to-Noise Ratio
SINAD – Signal-to-Noise and Distortion
Total Harmonic Distortion
23) is the ratio of the full-scale analog input (RMS value) to the RMS quantization error (residual
0...01
0...00
SNR
dB[MAX]
Input Voltage to Prescaler
Offset Error = 1.5 LSB
R e v i s i o n 1
Ideal Output
=
6.02
dB
×
N
+
1.76
Actel Fusion Family of Mixed Signal FPGAs
Actual Output
dB
EQ 23
2- 115