Rainbow Electronics MAX1033 User Manual
Page 29
Effective Number of Bits (ENOB)
ENOB indicates the global accuracy of an ADC at a
specific input frequency and sampling rate. With an
input range equal to the ADC’s full-scale range, calcu-
late the ENOB as follows:
Total Harmonic Distortion (THD)
For the MAX1032/MAX1033, THD is the ratio of the
RMS sum of the input signal’s first four harmonic com-
ponents to the fundamental itself. This is expressed as:
where V
1
is the fundamental amplitude, and V
2
through
V
5
are the amplitudes of the 2nd- through 5th-order
harmonic components.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio of RMS amplitude of the fundamental
(maximum signal component) to the RMS value of the
next-largest spectral component.
THD
V
V
V
V
V
log
=
×
+
+
+
20
2
2
3
2
4
2
5
2
1
ENOB
SINAD
.
.
=
−
1 76
6 02
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________
29
t
AD
t
AJ
INTCLK
(MODE 2)
ANALOG INPUT
TRACK AND HOLD
TRACK
HOLD
SAMPLE INSTANT
SCLK
(MODE 0)
13
14
15
SCLK
(MODE 1)
15
16
10
11
12
Figure 21. Aperture Diagram