Hi Glenn,
I saw this new product from Analog Devices
http://www.analog.com/en/clock-and-timing/pll-synthesizersvcos/adf4350/products/product.html
which seems like it may be a good choice for a flexible sampling clock
for CASPER projects. The evaluation board is cheaper than the Valon
boards at $175 and provides almost arbitrary frequency coverage
instead of predefined outputs around 500 and 1000 MHz. The phase noise
spec looks as good or better than the Valon as well. One disadvantage
is that it appears to be like other Analog Devices eval boards which
provides a Windows only USB interface. However, I have gotten around
this in the past using GPIO to interface directly to the SPI port on
the part.
Any opinions?
The first page of the data sheet lists the typical RMS jitter
as <0.4 ps rms. The aperture uncertainty/jitter of the e2v
AT84AD001B is about 0.4ps RMS, so together the total jitter
would be under ~sqrt(2)*0.4ps = 0.6ps RMS.
The aperture jitter limit for an 8-bit digitizer sampling a
1GHz signal is
ta < 1/(2*pi*fmax*2^N) = 0.6ps
So the expected jitter is right around the requirement
for 8-bit sampling. However, since no-one is actually using
all 8-bits from the ADC, a little more jitter could be
tolerated.
It sounds like this would be an ok clock source.
What is the jitter specification of the Valor?
Cheers,
Dave
