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leading
edge
Low-cost, high-signal-quality synthesized-clock
generator replaces RF synthesizer in many applications
tanford Research Systems' $2490 CG635
S synthesized-clock generator provides precise,
low-jitter digital-clock signals for applications
ranging from digital-circuit reduce aging, you can add an
design to communications- optional oven-stabilized crys-
network testing. You can set tal oscillator or rubidium fre-
the clock frequency from quency standard. You can also
0.001 Hz to 2.05 GHz. Rise lock the CG635 to an external
and fall times are as short as 10-MHz timebase. The CG635 synthesized-clock generator produces extremely clean, low-jit-
100 psec. Jitter is less than 1 Compared with a typical ter clock signals over a frequency range of 0.001 Hz to 2.05 GHz. The cost
psec rms. At 622.08 MHz, RF synthesizer, the CG635 has is a fraction of that of RF synthesizers, which, until now, have been the
phase noise at a 100-Hz offset many similarities: excellent only type of instrument suitable for producing many of the clock signals
is below a 80-dBc/Hz level, frequency resolution, low the new generator produces.
and the spurious response is phase noise, and low spurious
below a 70-dBc level. Using output levels. The new gener- The optional clock-receiver speed transitions at standard
the optional 10-MHz rubidi- ator offers several advantages, modules, which connect to the logic levels on SMA connec-
um timebase, aging is less however: output frequencies CG635 via Category 6 cable tors.--by Dan Strassberg
than 0.0005 ppm/year, and as low as 0.001 Hz, multiple and may be a substantial dis- Stanford Research Sys-
temperature instability is less square-wave outputs to 2.05 tance from the instrument, tems, 1-408-744-9040,
than 0.0001 ppm. GHz, and much lower cost. provide complementary high- www.thinksrs.com.
You can set the CG635 out-
puts to standard logic levels,
including CMOS, ECL (emit- Quad processors power new DSP board
ter-coupled logic), PECL Curtiss-Wright Controls Embedded Computing recently announced the Compact
(positive ECL), and LVDS Champ-AV IV, a high-performance CompactPCI DSP board that derives its power from
(low-voltage differential sig- four Freescale (www.freescale.com) MPC7448 PowerPC processors. The board complies
naling). You can also contin- with the CompactPCI packet-switching-backplane specification and provides DSP applica-
uously adjust offset and am- tions with as much as 48 GFLOPS of peak computational power. Each of the board's four
plitude between 5 and 5V. A processing nodes comprises a 1.5-GHz 7448 processor; 256 or 512 Mbytes of DDR-250
rear-panel output delivers SDRAM; dual 100-MHz, 64-bit PCI-X interfaces; and a Gigabit Ethernet connection. Each
clocks at RS-485 and LVDS node transfers data to adjacent nodes at speeds as high as 1.6 Gbytes/sec. Both PMC sites
levels over twisted pairs. An on the Compact Champ-AV IV support low-
optional PRBS (pseudoran- voltage differential signaling to the backplane
dom-binary-sequence) gen- connectors, enabling serial switched interconnec-
erator provides clock and data tions, such as StarLink and FibreChannel.
outputs at LVDS levels for Operating-system support for the Champ-AV
testing serial-data channels. IV includes Wind River (www.windriver.com)
Edge-transition times are VxWorks/Tornado. A Linux package will be
typically 80 psec. available by midyear. The Compact Champ-AV
The CG635's standard crys- IV is available in a commercial-temperature, air-
tal-oscillator timebase pro- cooled configuration with prices starting at
vides sufficient accuracy for The Compact Champ-AV IV delivers as much $14,900.--by Warren Webb
many applications. To im- as 48 GFLOPS of peak computational power Curtiss-Wright Controls Embedded Comput-
prove frequency stability and for advanced DSP applications. ing, www.cwcembedded.com.
According to IDC (www.idc.com), the worldwide storage-software market grew 15% year over year to $2.2 billion in the fourth quarter of
2004. For the full year 2004, storage-software revenue grew 16.1% year over year to $7.9 billion, injecting more than $1 billion of new rev-
enue into the market.
22 edn | April 14, 2005 www.edn.com