hi my name is Rick needs in Miami Senior Product Manager for key site
technologies today I'll be talking to you about some pan for measurements that
are made are performed on a real-time oscilloscope so we talk to you a little
bit about our setup here we have a key site see series 63 gigahertz
oscilloscope and we're using our relay channels that have full band without 263
gigahertz to receive a signal cam for signal that's operating at twenty eight
gig iPod or 28 Giga symbols per second can force a little bit different than
classical NRC type signal where the symbol rate essentially equates to the
bit rate is now in the case of PAM forward transmitting symbols and each
symbol has to bits by transmitting 28 gig a broader Giga symbols per second or
actually transmitting 56 Gigabit this is an important speed because we have
up-and-coming some YF 4.0 standards that will be operating at fifty-six gigabits
per second and some of those standards are you really specifying p.m. for as
one of the possible physical implementations so what I wanted to do
is to show you today after a couple of the measurements and you can make with a
real-time scope for these p.m. for measurements at 28 Chabad or 56 gigabits
per second so well first off and I'll show you the signal that we have here I
go in and I'll stop at this is the pan for signal and give you a sense of what
that looks like signaling standpoint there are four different levels and
there are basically each symbol represents two bits and looking at the
signal itself it tends to appear as an NRC signal with perhaps a lot of I aside
so by having some applications available on the oscilloscope you can greatly
facilitate your ability to do analysis of the pan for signal ok so go back to
run it
and let's just go through and I'll walk you through some of the steps to do this
now because
Samplitude modulation is becoming more popular we've added a new signal type
classification for the oscilloscope so we're going to signal type I will
specify the signal is being camphor and once we do that we bring up a whole
dialogue that allows us to go through and specify the parameters of the pan
for signal that we're measuring so we've got a pan for signal Setup window wizard
that we can run through that alaska's a couple of basic questions the first one
being the most important question is what's being every running out so we'll
go ahead and enter into speed which in this case happens to be 28 give up or
give you symbols per second
go on to the next one and then we can see that this is a twenty eight gig
about signal operating at fifty-six gigabits per cent the next thing is we
have to select what edges of the pan for signal we want to use in our clock
recovery and this can be very important because sometimes due to the distortion
of the signal if you transmitting this signal through a channel it can be
difficult for the clock recovery mechanism to differentiate between the
inter transitions of the 12 to 21 transitions so we're going to disable
those and just focus on seeking our clock 20 3230 edges to this is a very
powerful capability in our clock recovery tool that allows us to deal
with essentially very stressed signals and still be able to make measurements
on them now will go forward and the memory deaths picked automatically and
then the next step is to set the threshold so based along we've described
so far the software will do its best guess as to where these thresholds are
so prepare for this is important because it differential rear set the threshold
differentiates where the values are registered for the symbols whether
they're 0001 10
or 11 will depend upon where the thresholds are set so it doesn't initial
gas but to actually find out what those thresholds are for the particular signal
that we're driving it's going to look at it twice so first tool set up and I and
then we'll go back and internal row a couple of histograms at the levels and
then it will present to us the actual levels for each of those transitions so
we're gonna go ahead now and enable the few measurements we can do noise
measurements in this case I'm gonna do a couple of quick I measurements will be
looking at I with my height will also be looking at rise and fall times for each
of the eyes of her generation will go ahead and click on Finish soap m4 is
really becoming a more significant technology of late because there's a
desire to improve the throughput through a given channel but then to also do that
without having to incur additional penalties from operating in NRC signal
at those higher and higher rates as you know digital signal has to be able to
transmit its carrier or words Nyquist frequency through the channel and at the
higher the data rate the higher that Nyquist frequency tends to be the more
attenuation it will face in the channel that you drive it through so that being
the case we have now completed their setup and you can see we now have a plan
for measurement that is registered on screen very pleased that had this time
to spend with you and if you have any questions please contact us and use the
links that are provided below in this video
thank you