Datasheet

AD9833 Data Sheet
Rev. G | Page 10 of 21
TERMINOLOGY
Integral Nonlinearity (INL)
INL is the maximum deviation of any code from a straight line
passing through the endpoints of the transfer function. The end-
points of the transfer function are zero scale, a point 0.5 LSB
below the first code transition (000 … 00 to 000 … 01), and full
scale, a point 0.5 LSB above the last code transition (111 … 10
to 111 … 11). The error is expressed in LSBs.
Differential Nonlinearity (DNL)
DNL is the difference between the measured and ideal 1 LSB
change between two adjacent codes in the DAC. A specified
DNL of ±1 LSB maximum ensures monotonicity.
Output Compliance
Output compliance refers to the maximum voltage that can be
generated at the output of the DAC to meet the specifications.
When voltages greater than that specified for the output compli-
ance are generated, the AD9833 may not meet the specifications
listed in the data sheet.
Spurious-Free Dynamic Range (SFDR)
Along with the frequency of interest, harmonics of the funda-
mental frequency and images of these frequencies are present at
the output of a DDS device. SFDR refers to the largest spur or
harmonic present in the band of interest. The wideband SFDR
gives the magnitude of the largest spur or harmonic relative to
the magnitude of the fundamental frequency in the zero to Nyquist
bandwidth. The narrow-band SFDR gives the attenuation of the
largest spur or harmonic in a bandwidth of ±200 kHz about the
fundamental frequency.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of harmonics to the rms value
of the fundamental. For the AD9833, THD is defined as
1
2
6
2
5
2
4
2
3
2
2
log20THD
V
VVVVV ++++
=
where:
V
1
is the rms amplitude of the fundamental.
V
2
, V
3
, V
4
, V
5
, and V
6
are the rms amplitudes of the second
through sixth harmonics.
Signal-to-Noise Ratio (SNR)
SNR is the ratio of the rms value of the measured output signal
to the rms sum of all other spectral components below the
Nyquist frequency. The value for SNR is expressed in decibels.
Clock Feedthrough
There is feedthrough from the MCLK input to the analog
output. Clock feedthrough refers to the magnitude of the
MCLK signal relative to the fundamental frequency in the
output spectrum of the AD9833.