Terminology - Analog Devices AD9739 Manual

AD9739

TERMINOLOGY

Linearity Error (Integral Nonlinearity or INL)
The maximum deviation of the actual analog output from the
ideal output, determined by a straight line drawn from zero to
full scale.
Differential Nonlinearity (DNL)
The measure of the variation in analog value, normalized to full
scale, associated with a 1 LSB change in digital input code.
Monotonicity
A DAC is monotonic if the output either increases or remains
constant as the digital input increases.
Offset Error
The deviation of the output current from the ideal of zero is
called the offset error. For IOUTP, 0 mA output is expected
when the inputs are all 0s. For IOUTN, 0 mA output is expected
when all inputs are set to 1.
Gain Error
The difference between the actual and ideal output span. The
actual span is determined by the output when all inputs are set
to 1 minus the output when all inputs are set to 0.
Output Compliance Range
The range of allowable voltage at the output of a current output
DAC. Operation beyond the maximum compliance limits may
cause either output stage saturation or breakdown, resulting in
nonlinear performance.
Temperature Drift
Specified as the maximum change from the ambient (25°C)
value to the value at either T
drift, the drift is reported in ppm of full-scale range (FSR)
per °C. For reference drift, the drift is reported in ppm per °C.
or T . For offset and gain
MIN MAX
Power Supply Rejection
The maximum change in the full-scale output as the supplies
are varied from nominal to minimum and maximum specified
voltages.
Spurious-Free Dynamic Range
The difference, in decibels (dB), between the rms amplitude of
the output signal and the peak spurious signal over the specified
bandwidth.
Total Harmonic Distortion (THD)
The ratio of the rms sum of the first six harmonic components
to the rms value of the measured input signal. It is expressed as
a percentage or in decibels (dB).
Noise Spectral Density (NSD)
NSD is the converter noise power per unit of bandwidth. This
is usually specified in dBm/Hz in the presence of a 0 dBm full-
scale signal.
Adjacent Channel Leakage Ratio (ACLR)
The adjacent channel leakage (power) ratio is a ratio, in dBc,
between the measured power within a channel relative to its
adjacent channels.
Modulation Error Ratio (MER)
Modulated signals create a discrete set of output values referred
to as a constellation. Each symbol creates an output signal
corresponding to one point on the constellation. MER is a
measure of the discrepancy between the average output symbol
magnitude and the rms error magnitude of the individual
symbol.
Intermodulation Distortion (IMD)
IMD is the result of two or more signals at different frequencies
mixing together. Many products are created according to the
formula aF1± bF2, where a and b are integer values.
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