AD9862-EBZ Analog Devices Inc, AD9862-EBZ Datasheet - Page 21
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AD9862-EBZ
Manufacturer Part Number
AD9862-EBZ
Description
BOARD EVALUATION FOR AD9862
Manufacturer
Analog Devices Inc
Type
ADC + DAC, Codec, Front End for RFr
Datasheet
1.AD9860-EBZ.pdf
(32 pages)
Specifications of AD9862-EBZ
For Use With/related Products
AD9862
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
In most systems, the DAC (and each up-converter stage) requires
analog filtering to meet spectral mask and out-of-band spurious
emissions requirements. Digital interpolation (Block C) and
Hilbert filtering (Block E) can be used to relax some of the system
analog filtering.
Digital 2 interpolation with input data rates of up to 64 MSPS or
4
in this mode (or interpolation filters can be bypassed to achieve
a 128 MSPS input data rate). The data bandwidth with 2 or
4
no interpolation is enabled, the data bandwidth will be the full
Nyquist band with Sinc
are configured through the Interpolation Serial register.
The Hilbert filter can be enabled in this mode to suppress the
positive or negative image that naturally occurs with real data.
The single sideband signal when combined with a quadrature
modulator can upconvert the desired signal and suppressed image,
forming a Hartley Image Rejection Architecture (both Tx paths
need to be enabled to produce the Image Rejection Architecture).
The Hilbert filter will provide over 50 dB image suppression for
signals between 12.5% to 38% of the input data rate. The Hil-
bert filter can be enabled and configured using the Hilbert and
Keep –ve Serial registers.
Digital frequency tuning the Tx output is also possible in this
mode using the coarse modulation block. The coarse modulation
block can be used to frequency shift the Tx signal either –f
–f
require the Hilbert filter to be enabled, in which case the real
signal and image will shift. If the Hilbert filter is enabled, a
complex mix can be performed on the single sideband signal by
the coarse modulator (Note: the Hilbert filter does not need to
be enabled if single sideband data is provided externally).
The fine modulator can be used to accurately place the output
signal shifting the Tx data spectrum in the positive or negative
direction with a resolution of f
requires both 4
be used in this mode. The coarse modulator and fine modulator
can both be used and provide a tuning range between ± 68% of
the DAC Nyquist frequency.
If all Tx DSP blocks are bypassed, the AD9860/AD9862 oper-
ates similar to a standard TxDAC. In Single Channel DAC Data
mode, only the Channel A DAC is used; Channel B is powered
down to reduce power consumption.
Two Independent Real Signal DAC Data
The Dual Channel Real DAC Data mode is used to transmit
diversity or dual channel signals. In this mode, 12-/14-bit, dual
channel, interleaved Tx data is provided to the AD9860/AD9862
and latched using either CLKOUT1 or CLKOUT2 edges as
defined in the Clock Overview section of the data sheet. Both
Tx paths are enabled and the two signals will be processed
REV. 0
DAC
interpolation with input data rates of 32 MSPS is available
interpolation enabled is up to 38% of the input data rate. If
/8, +f
DAC
/8 or +f
interpolation and the Hilbert filter enabled to
DAC
/4. The coarse modulator does not
limitations. The interpolation filters
DAC
/2
26
. The fine modulator
DAC
/4,
–21–
independently. The Tx digital processing blocks available in this
mode are the Interpolation Filters (Block C) and the Coarse
Modulator (Block D).
As mentioned previously, the interpolation filters can be used to
relax requirements on the external analog filters. The maximum
rate of the Tx interface is 128 MSPS, i.e., 64 MSPS/channel
with interleaved data. Therefore to fully take advantage of the
DACs maximum update rate of 128 MSPS, 2 interpolation is
required. The 4 interpolation filter is recommended for input
data rates equal to or less than 32 MSPS/channel (64 MSPS
interleaved). The data bandwidth with 2 or 4
enabled is up to 37.5% of the channel input data rate. If no
interpolation is enabled, the data bandwidth will be the full
Nyquist band with Sinc
are configured through the Interpolation Serial register.
The coarse modulation will perform a real mix of each channel,
independently, with either f
Dual Channel Complex DAC Data
The Dual Channel Complex DAC Data (also known as Single
Sideband Data) is used to generate complex Tx signals (i.e., I and
Q). In this mode, 12-/14-bit, interleaved I and Q data is provided
to the AD9860/AD9862 and latched using either CLKOUT1 or
CLKOUT2 edges as defined in the Clock Overview section of
the data sheet. Both Tx paths are enabled and the two signals
will be processed as a complex waveform. The Tx digital pro-
cessing blocks available in this mode are the Fine Modulator
(Block B), the Interpolation Filters (Block C), and the Coarse
Modulator (Block D).
As mentioned previously, the interpolation filters can be used to
relax requirements on the external analog filters. The maximum
rate of the Tx interface is 128 MSPS, i.e., 64 MSPS/channel with
interleaved data (as is the case in this mode). Therefore, to fully
take advantage of the DAC’s maximum update rate of 128 MSPS,
2 interpolation is required. The 4 interpolation is recommended
for input data rates equal to or less than 32 MSPS/channel
(64 MSPS interleaved). The data bandwidth with 2 or 4
interpolation enabled is up to 37.5% of the channel input data
rate. If no interpolation is enabled, the data bandwidth will be
the full Nyquist band with Sinc
filters are configured through the Interpolation Serial register.
A complex mix can be performed on the single sideband signal
by the coarse and/or fine modulator. The coarse modulation
block can be used to frequency shift the Tx signal either –f
–f
accurately place the output signal shifting the Tx data spectrum
in the positive or negative direction with a resolution of 1/2
the DAC update rate. The fine modulator requires 4 interpola-
tion to be enabled. The coarse modulator and fine modulator
can both be used and provide a tuning range between ± 70% of
the DAC Nyquist frequency.
DAC
/8, +f
DAC
/8 or + f
DAC
/4. The fine modulator can be used to
limitations. The interpolation filters
DAC
/4 or f
AD9860/AD9862
limitations. The interpolation
DAC
/8.
interpolation
DAC
26
/4,
of