Ordering Guide - Analog Devices HSC-ADC-EVALA-SC Manual

HSC-ADC-EVALA-SC/HSC-ADC-EVALA-DC
was not actually taken in the equation above, leaving the
magnitude expressed as the sum of two squares. Therefore
10 × log is used instead of 20 × log, eliminating the time
required to compute the square root.
Based on Nyquist Theory, the encode rate must be at least twice
the signal bandwidth to faithfully represent the signal when
sampled. Therefore, if the encode rate is 80 MHz, an ADC can
only represent 40 MHz of continuous bandwidth. Knowing the
encode rate and the number of time-domain samples, the
frequency representation per bin can be established. In this
example, the encode rate is 80 MHz and there are 16,384 time-
domain samples; therefore, 4880 Hz/bin is represented. If the
encode rate is doubled or the number of time-domain samples
is doubled, a 3 dB improvement in the noise floor is observed.
This does not represent an improvement in ADC performance,
but simply represents an increased resolution per bin.
From the computations above, it is now possible to define and
calculate SNR, SINAD, harmonics, SFDR, ENOB, and noise
figure. The signal-to-noise ratio can be expressed as the ratio of
the rms signal amplitude to the rms value of the sum of all
other spectral components, excluding the first six harmonics
and dc, or by the equation:

ORDERING GUIDE

Model
HSC-ADC-EVALA-SC
HSC-ADC-EVALA-DC
1
AD922XFFA
1, 2
AD664XFFA
1
AD9432FFA
1
AD9283FFA
AD9071FFA 1
1
AD9059FFA
AD9051FFA 1
1
LG-0204A
1
If an adapter is needed, send an email to
2
Required for Revision C of AD6644 and AD6645 evaluation boards. Revision D and greater are directly compatible with e HSC-ADC-EVALA-SC evaluation board
© 2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
Description
Single FIFO Version of USB Evaluation Kit
Dual FIFO Version of USB Evaluation Kit
Adapter for AD922x Family (Not included in Evaluation Kit)
Adapter for AD664x Family (Not included in Evaluation Kit)
Adapter for the AD9432 (Not included in Evaluation Kit)
Adapter for the AD9283 and AD9057 (Not included in Evauation Kit)
Adapter for the AD9071 (Not included in Evaluation Kit)
Adapter for the AD9059 (Not included in Evaluation Kit)
Adapter for the AD9051 (Not included in Evaluation Kit)
Adapter for the AD10xxx and AD13xxx Families (Not included in Evaluation Kit)
highspeed.converters@analog.com
C04750-0-5/04(0)
Rev. 0 | Page 44 of 44
= ×
SNR 20 log
Noise_Energy represents the summation of all the noise energy
in the spectrum, and Fundamental_Energy represents the
summation of the fundamental energy. The fundamental energy
resides in a single bin if a coherent system is used; however, in
the case of a windowing function, it may be spread over 10 to 25
bins, depending on the windowing technique.
Harmonics can be defined as the ratio of the rms signal
amplitude to the rms value of the harmonic component,
reported in dBc. Harmonics represent the nonlinearities within
the ADC and are integer multiples of the fundamental. If the
harmonic exceeds fs/2, it will be aliased back into the first
Nyquist zone. A concept closely related to harmonics is SFDR.
For an ADC, SFDR is defined as the ratio between the rms
amplitude of a single tone and the rms amplitude of the worst
spur as the tone is swept through the entire ADC input range. It
is very common for the worst spur to be harmonically related.
Whereas SNR excludes the first five harmonics, SINAD includes
these harmonics as part of the Noise_Energy summation,
otherwise known as THD or Total Harmonic Distortion. If the
harmonic performance of the ADC is excellent, there is very
little difference between the SNR value and the SINAD value.
with the part number of the adapter and a mailing address.
⎛
⎞
Fundamenta l_Energy
⎜
⎟
dB
⎟
⎜
10
Noise_Ener gy ⎠
⎝