Pentek Model 78741 Installation Manual
Page 27
Rev.: 2.5
2.11
XMC Panel Connections
The 71741 XMC front panel, illustrated at the right, fits into the
slot opening on the PCIe carrier. See
location of the panel on the Model 78741. The front panel
includes a 19−pin
μ
Sync connector and four SSMC coaxial
connectors for input/output of analog and digital signals.
These connectors are described in the following subsections.
The front panel also includes five LED indicators. These are
described in
2.11.1
PPS Input Connector
PPS IN
The front panel has one SSMC coaxial connector,
labeled
PPS IN
, for input of an external PPS or Gate
signal. The input TTL signal must be a full−scale
level of 1.65V to 5.5V. Use the Sync Bus Control
Register (see the
Model 71741 Operating Manual
) to
select the PPS IN signal as a Gate to control ADC
data packing.
2.11.2
Analog Input Connectors
IN 1, IN 2
The front panel has two SSMC coaxial connector, labeled
IN 1
and
IN 2
, for
analog signal inputs to the ADC12D1800 A/D converter.
IN 1
is connected
to the ADC12D1800 I input;
IN 2
is connected to the Q input. Each analog
input signal has a full−scale level of +2 dBm to +4 dBm, programmable.
Each input drives an RF transformer with 50 Ohms input impedance.
Note
The
PPS IN
input is 5V tolerant, but it must
NOT have any negative voltage applied.
It is terminated with a 392
−
Ohm resistor to
3.3V and a 392
−
Ohm resistor to ground.
Note
The ADC12D1800 will not operate properly until it is initialized using the
ADC Serial Address and Data Registers (see the
Model 71741 Operating
Manual
). Pentek’s ReadyFlow Board Support Packages provide functions
to perform this initialization.
For single
−
channel operation (ADC12D1800 DES mode), the
ADC12D1800 power
−
on/reset default uses
IN 2
as the signal input.
The ADC12D1800 power
−
on/reset default input level is +2 dBm. Use the
ADC Serial Address and Data Registers(see the
Model 71741 Operating
Manual
) to program different input levels, from +2 dBm to +4 dBm.
Figure 2
−
9:
71741 XMC
Front Panel
