The Wireless Gigabit Alliance’s 60-GHz-based high-definition
wireless-video-transport scheme may be on the way, but SiBeam’s
pioneering approach and multiple product generations are already
on the scene (see “The quest for robust wireless high-def video
, Sept 23, 2010, pg 32).
Peer inside a SiBeam-developed reference design to see how the company
accomplishes this hefty bit-rate trick, complete with support for 3-D video
presentations and for equipment control and networking augmentations.
The transmitter and receiver, each measuring
9×6×1.5 in., are identical except for backpanel
labels that identify them as “source”
and “sink,” respectively. An external ac
adapter with 12V and 1.7A maximum output
specifications powers each of them.1.
Take off the top covers of the transmitter’s and receiver’s
enclosures, and you’ll find that a USB (Universal Serial Bus)-interface PCB (printed-circuit board) takes
up most of the internal space. This debugging and control
board mates with PC-side software, and production-system
designs won’t need it. Such designs can be substantially
smaller, less costly, and more power-thrifty as a result.2.
Behind the units’ plastic front panels and underneath intermediary
metal shields that block all but the transmitting
and receiving antenna arrays are 22×125×6-mm PCBs
containing the core circuitry for each device. In this case,
too, however, some of the silicon content is exclusive to the
evaluation task and won’t appear in a production design.
To wit, the top sides of both the transmitter and the receiver
modules include Atmel AT91SAM256 microcontrollers to
implement stand-alone operation. In an end-customer
design, such as a Blu-ray player, a set-top box, a television,
or an integrated home-theater setup, the system processor
will typically manage the module, making the dedicated
SiBeam’s SB9220 HRTX (high-resolution-transmitter) WirelessHD (high-definition) network processor
sits on the transmitter module’s top side. The SB9210 HRTX
RF transceiver is alongside it and underneath a ceramic
microantenna-array lid. Corresponding ICs on the receiver
module’s top side are the SB9221 HRRX WirelessHD network
processor and SB9211 HRRX (high-resolution-receiver) RF transceiver. These
latest-generation chip sets handle 1080p-resolution video at
60-Hz frame rates, with color depth as high as 4:4:4. They
also comprehend HDMI’s (high-definition multimedia interface’s) CEC (consumer-electronics-control) feature, as well as WVAN (wireless video-area network).
WVAN support provides the ability for a video source, such
as a PC or a game console, to automatically be aware of
(and for its user to subsequently select among) various available
destination display devices and for a user (at a destination
display) to select among available video sources.4.
A California Micro Devices ESD (electrostatic-discharge)-protection chip clamps transients
originating from the HDMI connector on the receiver module. The
transmitter implements ESD protection for its TMDS (transition-minimized differential-signaling) lines using
discrete components. In this case, the HDMI connector mounts
on the module back. SiBeam also makes evaluation modules for
LVDS (low-voltage differential signaling) and LVCMOS (low-voltage complementary-metal-oxide-semiconductor) video interfaces. Also visible on both modules’
backs are the power- and system-processor-control interfaces.