Beatty and a Tick (or DesignCon in two Hours)

Leaving Flipjack

Early morning on the last day of DesignCon 2018.
I am still in FlipJack and this is not my breakfest:

No, as I did not know that when making a reservation to a "Bead and Breakfest" then BREAKFEST is EXLUDED from the room price by DEFAULT. So I only got a morning coffee.

Should I go to DesignCon or maybe I should enjoy the rest of the day walking? I decide to admire the looks and forget about DesignCon so I pack all my things into a light backpack that I can carry comfortably and put all the things I do not need that much into a trashbin. Ready! It's about 20 kilometers to walk so I estimate some 4+ Hours for it. Final check before leaving - do I have all my items with me? I'm standing at FlipJacks front door, taking a last look. At left back corner I see some bread on the Table. It's 4 hours walk and not much chance to get any food on the way, what I have is one small bottle of water. Could I take a slice of bread? I am hesitating a moment. At checkin when I was introduced to the Cowgirl room, I was told at a small fridge: "all this is free". All this was 4 small bottles of water. So I made a safe conclusion that if I assume that everything else eatable or trinkable is for extra charge I would be fine. So I leave the bread on the table untouched.

On the way down on Bonny Doon road. Automatic panaroma pic prepared by google photos.

You can get dizzy at the look at this look!

After a while the landscape is about to change. And then I see an human - he comes towards me and shakes my hand: "I'm Dave!" he says. A few minutes later I get up into the back of his SUV-Truck. Dave gives me a ride to Santa Cruz.

Thanks to Dave I am pretty much early in Santa Cruz, so I decide to check if I can catch a bus to Santa Clara early enough to still visit DesignCon. And luckily google maps tell me that the very next bus would take me in time to have about two hours at the Conference. Well if I catch that bus. I arrive at bus terminal about two minutes before the departure time!

"Did you got your solarpowered battery-backup back?" - I am looking at young female bus driver with long black hair.
"Eh?" is all I can respond.

"Did you got your solarpowered battery-backup back?" she repeats the question and explains: "you left it in my bus, on the back seat, didnt you? I left it at bus-terminal for you to pickup.."

"Ah, yes probably" I respond. I am trying to pay for the trip. Suddenly she starts to talk in spanish. We argue several minutes. I explain that I will NOT STEP OUT from her bus (not at time the bus should already depart) to get my batterypack back no matter it is maybe less 30 meters to walk. I want stay in this bus, this is really important! I want to stay, I want to be sure I do get to Santa Clara with this bus. I speak in english. She is talking in pure spanish. I know no Spanish. Well, finally she gives up and I pay for the trip. I sit down.

A Tick

Just a few minutes before I got to the bus I did feel some itching-pain on my left foot about the height of the pants pockets. I assumed it must be some sharp pin or piece of redwood or from some plant. The pain was surprisingly strong and did not go away immediately. But when I was seated on the bus I had already forgotten about it.

Well, it was a Tick. 

It was a DEER TICK, the large brown one. 

The bad one. 

I paid 311 USD the next day to a doctor at Union Square in San Fransisco. The pills he gave to me had to be taken for two weeks. Well, my family doctor says that they should be taken 21 days, so I buy some more at home. My insurance (german AOK) does not cover USA. Mastercard pays some 100 EUR from the bill. Well I am really happy that I did go to the doctor. Because this tick was really a baddy, in 12 hours from the bite the skin around it was darker with diameter of 8 cm or so. But what really made me think about the luck - even 7 weeks after the bite the skin around the bite is still bit darker with a diameter of 1 centimeter or so. I have been biten by ticks uncounted times when I was a child, more than 10 times each summer maybe. But the deer tick was something new. Next time I will not hesitate to check out an itch while in the USA or any other region where bad ticks can be found.

A beatty

So WHAT is beatty? Ah this is a very simple thing, I think it is a PCB trace that is 3 times the width of the transmission line and about one inch long. That's all folks! Something that looks like this:

While it just looks like a simple thing it enables a lot of magic for signal integrity testing and measurement and and and and if you go beyond 10 GHz. I am guessing it is used as a standard test fixture in the P370.

Wait but what is P370? Well, it is some IEEE Project that is about to become a standard.

And yes I did see a real:

BEATTY

at DesignCon 2018. I did arrive about 1500 or so at the Conference Hall on the last day.

"Can I join the 2:50 talk?" I ask at Ballroom E Entrance, I am trying to explain that I have that 99$ EXPO+ Pass.
No, that pass does not allow you to go there, but wait I can sneak you in if you want! Do you have your badge?
"No I explain, I forgot all that paperwork somewhere :(".
"You really need the badge", the older lady explains, you go all the way in that direction, they will give your a badge!
I sprint. It is really cool to run inside Santa Clara Conference Centre with Salomon SpeedCross 4 cross country running shoes.

The traction is perfect. Huh... I am back at Ballroom E. I get my badge scanned and I can enter the session. It was pretty interesting. Now my speedcross shoes allow me a fast movement on the pathways and inside the expo hall as well. I only have few hours so I am trying to get out the most there is.

At one desk there is a quiz, the question is which one has smaller inductance:

I look and laugh. The guys are starting to explain that what their tools can do etc. I smile and say that there are no tools needed to solve their quiz, the track lower with two small holes has smaller inductance than the one large via.
This quiz actually is simple to solve by using the brain only, and even without deeper knowledge or experience.

One way to get to the right answer: if you look very quick then it is obvious that most visitors would tend to select the larger via as the one with smaller inductance. So this means that it is the wrong answer.

A second way to get to the right answer needs some closer look at the via structures. The larger via is really large, but it connects to a narrow trace. So most of the via copper is DEAD copper for high frequency. It is of course impossible to calculate in the brains how much of the copper is dead and do a valid comparison. But it already gives a hint that the larger via is not used in an optimal way. So the choice that two small vias are better is close.

Sure the software that as advertised at that booth delivers the same result. The two small vias have smaller inductance than the one large one.

Too simple.

I continue running between the booths monitoring the queue lengths for pizza and beer. It's conference happy hour time now!

Antti
(Blog entry written almost two months after DesignCon)