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HARDWARE ARCHITECTURE
SYNTH300 series boards are comprised of a digital section and an analog section. The digital section
includes a high speed programmable logic device which implements the PCI interface and embedded
firmware for controlling the DDS cores of the analog section. The analog section contains a 1GHz low-
jitter clock, and two single-chip Direct Digital Synthesizer (DDS) ICs. The current outputs of each
DDS are fed to a broadband RF transformer and 300MHz low-pass filter.
SYNTHESIZER A & B OUTPUTS (DDS A OUT, DDS B OUT)
The two analog synthesizer outputs are provided on SMA connectors with amplitude (nominally 200mV
RMS into 50 ohms). The frequency, phase, frequency sweep rate (if specified), and other parameters
are software programmable. A wide range of 50 ohm coaxial attenuators, such as those available from
Mini-Circuits (Brooklyn, NY) may be used in conjunction with the board.
LVDS OUTPUTS LVDSB+, LVDSB-
The two LVDSB output lines are driven by a TI SN65LVDS100DGK LVDS driver, which receives the
output generated by DDSB, after filtering.
TRIG/MODA AND TRIG/MODB I/O LINES
The MODA and MODB jacks are used as profile selection inputs, or ARM/SWEEP control inputs, in
standard operation (boards without the LVDSX2 option). If the MODB input is not required for profile
selection, it may be alternatively jumpered so as to provide a 125MHz clock output or a TTL version of
the SynthA output, as shown below.
Figure 4.1 ModA and ModB Input / Output jack jumper configuration
In boards with the LVDSX2 option, the TTL TRIG/MODA & TRIG/MODB jumpers are removed, and the
TRIG/MODA and TRIG/MODB jacks are used for the LVDSA+ and LVDSA- outputs, respectively. This
removes the ablity of these jacks to be used for external modulation capability. If the user desires to
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TRIG/MODA JACK
TRIG/MODB JACK
Remove jumper for LVDSA+ output
(option LVDSX2 only)
Remover jumper for LVDSA- output
(option LVDSX2 only)
TRIG/MODA JACK
Jumper installed (default) for MODA input
TRIG/MODB JACK
Jumper installed (default) for MODB input
TRIG/MODB JACK
Jumper installed for 125MHz CLK output
Or second SynthA output