WHITE PAPER
COTS Software Defined Radio for 5G Development
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An SDR transmitter accepts digital information to
be transmitted and then performs the necessary
DSP operations to produce digital samples for a
D/A converter, whose analog output signal drives a
PA for delivery to the antenna (see figure 1c).
Because these radios are software defined, they can be
programmed on-the-fly with new parameters in microseconds,
or re-configured for many different purposes by simply loading
a new firmware image from internal or external memory.
An SDR is often implemented on a specialized PCB board
called a "mezzanine card". The current generation of these
cards is a switched-fabric mezzanine card, an XMC or an
FPGA mezzanine card, an FMC. Figure 2a contains an image
of an XMC and FMC mezzanine card with the corresponding
functional block diagram to the right. Image A is an XMC card
Figure 2a
An SDR receiver converts an RF signal from an antenna
into digital samples with an A/D converter and uses
subsequent DSP operations to extract the required
information from the signal (see figure 1b).
Figure 1c
with four 200 MHz A/D channels, and image B is an FMC card
with two 3.0 GHz A/D channels, and two 2.8 GHz D/A channels.
Either of these mezzanine cards can be combined with a
different form-factor carrier for installation in a different
chassis, or on a PC motherboard. The primary difference is
the FMC mezzanine card on Figure 2b does not include an
FPGA and requires a more complex carrier card. This concept
allows the same mezzanine card and carrier combination
to be used on different platforms in multiple systems.
>
RF Coaxial Connectors
>
FPGA
>
XMC
Connectors
>
XMC Mezzanine Card
Functional Block Diagram
