Clock N

Clock N + 7

Sample N + 7

Sample N + 6

Sample N

Sample N + 8

Sample N + 9

Sample N + 10

CLK

DA0 - DA11

Data N + 2

Data N - 1

90%

10%

90%

10%

1

Data N + 1

DB0 - DB11

DRDY

Data N

ADC12DC080

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SNAS405B – SEPTEMBER 2007 – REVISED NOVEMBER 2008

SIGNAL TO NOISE RATIO (SNR) is the ratio, expressed in dB, of the rms value of the input signal to the rms

value of the sum of all other spectral components below one-half the sampling frequency, not including

harmonics or DC.

SIGNAL TO NOISE PLUS DISTORTION (S/N+D or SINAD) Is the ratio, expressed in dB, of the rms value of the

input signal to the rms value of all of the other spectral components below half the clock frequency, including

harmonics but excluding d.c.

SPURIOUS FREE DYNAMIC RANGE (SFDR) is the difference, expressed in dB, between the rms values of the

input signal and the peak spurious signal, where a spurious signal is any signal present in the output spectrum

that is not present at the input.

TOTAL HARMONIC DISTORTION (THD) is the ratio, expressed in dB, of the rms total of the first six harmonic

levels at the output to the level of the fundamental at the output. THD is calculated as:

(3)

6 harmonic frequencies in the output spectrum.

SECOND HARMONIC DISTORTION (2ND HARM) is the difference expressed in dB, between the RMS power in

the input frequency at the output and the power in its 2nd harmonic level at the output.

THIRD HARMONIC DISTORTION (3RD HARM) is the difference, expressed in dB, between the RMS power in

the input frequency at the output and the power in its 3rd harmonic level at the output.

Timing Diagrams

Figure 1. Output Timing

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