Pentek 6230 Operating Manual page 93

DEFINITIONS OF SPECIFICATIONS
Analog Bandwidth
The analog input frequency at which the spectral power of the
fundamental frequency (as determined by the FFT analysis) is
reduced by 3 dB.
Aperture Delay
The delay between the 50% point of the rising edge of the
ENCODE command and the instant at which the analog input
is sampled.
Aperture Uncertainty (Jitter)
The sample-to-sample variation in aperture delay.
Differential Analog Input Resistance, Differential Analog Input
Capacitance, and Differential Analog Input Impedance
The real and complex impedances measured at each analog
input port. The resistance is measured statically and the capaci-
tance and differential input impedances are measured with a
network analyzer.
Differential Analog Input Voltage Range
The peak-to-peak differential voltage that must be applied to the
converter to generate a full-scale response. Peak differential voltage
is computed by observing the voltage on a single pin and sub-
tracting the voltage from the other pin, which is 180 degrees out
of phase. Peak-to-peak differential is computed by rotating the
inputs phase 180 degrees and taking the peak measurement again.
The difference is then computed between both peak measurements.
Differential Nonlinearity
The deviation of any code width from an ideal 1 LSB step.
Encode Pulsewidth/Duty Cycle
Pulsewidth high is the minimum amount of time that the
ENCODE pulse should be left in Logic 1 state to achieve rated
performance; pulsewidth low is the minimum time ENCODE
pulse should be left in low state. See timing implications of
changing t in text. At a given clock rate, these specs define
ENCH
an acceptable ENCODE duty cycle.
Full-Scale Input Power
Expressed in dBm. Computed using the following equation:
=
Power
Full Scale
Harmonic Distortion, 2nd
The ratio of the rms signal amplitude to the rms value of the
second harmonic component, reported in dBc.
Harmonic Distortion, 3rd
The ratio of the rms signal amplitude to the rms value of the
third harmonic component, reported in dBc.
Integral Nonlinearity
The deviation of the transfer function from a reference line
measured in fractions of 1 LSB using a "best straight line"
determined by a least-square curve fit.
REV. 0
 
2
V
Full Scale rms
 
| | Z
 
Input
10 log
 
0 001 .
 
 
Minimum Conversion Rate
The encode rate at which the SNR of the lowest analog signal
frequency drops by no more than 3 dB below the guaranteed limit.
Maximum Conversion Rate
The encode rate at which parametric testing is performed.
Output Propagation Delay
The delay between a differential crossing of ENCODE and
ENCODE and the time when all output data bits are within
valid logic levels.
Noise (For Any Range Within the ADC)
=
V | | Z
NOISE
Where Z is the input impedance, FS is the full scale of the device
for the frequency in question, SNR is the value for the particular
input level and Signal is the signal level within the ADC reported
in dB below full scale. This value includes both thermal and
quantization noise.
Power Supply Rejection Ratio
The ratio of a change in input offset voltage to a change in power
supply voltage.
Signal-to-Noise-and-Distortion (SINAD)
The ratio of the rms signal amplitude (set 1 dB below full scale)
to the rms value of the sum of all other spectral components,
including harmonics, but excluding dc.
Signal-to-Noise Ratio (Without Harmonics)
The ratio of the rms signal amplitude (set at 1 dB below full scale)
to the rms value of the sum of all other spectral components,
excluding the first five harmonics and dc.
Spurious-Free Dynamic Range (SFDR)
The ratio of the rms signal amplitude to the rms value of the peak
spurious spectral component. The peak spurious component may
or may not be a harmonic. May be reported in dBc (i.e., degrades
as signal level is lowered), or dBFS (always related back to con-
verter full scale).
Two-Tone Intermodulation Distortion Rejection
The ratio of the rms value of either input tone to the rms value
of the worst third order intermodulation product; reported in dBc.
Two-Tone SFDR
The ratio of the rms value of either input tone to the rms value
of the peak spurious component. The peak spurious component
may or may not be an IMD product. May be reported in dBc
(i.e., degrades as signal level is lowered), or in dBFS (always
related back to converter full scale).
Worst Other Spur
The ratio of the rms signal amplitude to the rms value of the worst
spurious component (excluding the 2nd and 3rd harmonic)
reported in dBc.
–7–
AD6644
 
FS – Signal
dBm dBFS
 
 
× ×
10
0 001 10 .