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dc1884af
DEMO MANUAL DC1884A
QUICK START PROCEDURE
Encode Clock
Note: Apply an encode clock to the SMA connector on
the DC1884 demonstration circuit board marked “J2
CLK
+
.” As a default, the DC1884 is populated to have a
single-ended input.
For the best noise performance, the ENCODE input must
be driven with a very low jitter, square wave source. The
amplitude should be large, up to 3V
P-P
or 13dBm. When
using a sinusoidal signal generator, a squaring circuit can
be used. Linear Technology also provides demo board
DC1075A that divides a high frequency sine wave by four,
producing a low jitter square wave for best results with
the LTM9011.
Using bandpass fi lters on the clock and the analog input will
improve the noise performance by reducing the wideband
noise power of the signals. In the case of the DC1884 a
bandpass fi lter used for the clock should be used prior
to the DC1075A. Data sheet FFT plots are taken with 10
pole LC fi lters made by TTE (Los Angeles, CA) to suppress
signal generator harmonics, non harmonically related
spurs and broadband noise. Low phase noise Agilent
8644B generators are used for both the clock input and
the analog input.
Digital Outputs
Data outputs, data clock, and frame clock signals are
available on J1 of the DC1884. This connector follows the
VITA-57/FMC standard, but all signals should be verifi ed
when using an FMC carrier card other than the DC1371.
Software
The DC1371 is controlled by the PScope system software
that can be downloaded from the Linear Technology website
at
http://www.linear.com/software/
.
To start the data collection software, “PScope.exe,” which is
installed by default to \Program Files\LTC\PScope\, double
click the PScope icon or bring up the run window under
the start menu, and browse to the PScope directory and
select “PScope.”
If the DC1884 is properly connected to the DC1371, PScope
should automatically detect the DC1884 and confi gure
itself accordingly.
If everything is hooked up properly and a powered and
suitable convert clock is present, clicking the “Collect”
button should result in time and frequency plots displayed
in the PScope window. Additional information and help for
PScope is available in the DC1371 Quick Start Guide, and
in the online help feature within the PScope program itself.
