One Protocol to Rule Them All!? – #34

The USB Type-C brings a lot of protocols into one physical connector, but is there room for one protocol to handle all our IO needs? Mike Hoffman and Daniel Bogdanoff sit down with high speed digital communications expert Jit Lim to find out.

USB Type-C brings a lot of protocols into one physical connector, but is there room for one protocol to handle all our IO needs? Mike Hoffman and Daniel Bogdanoff sit down with high speed digital communications expert Jit Lim to find out.

 

0:00 This is Jit’s 3rd podcast of the series

1:00 We already have one connector to rule them all with USB Type-C, but it’s just a connector. Will we ever have one specification to rule them all?

2:00 Prior to USB Type-C, each protocol required it’s own connector. With USB TYpe-C, you can run multiple protocols over the same physical connector

3:00 This would make everything more simple for engineers, they would only need to test and characterize one technology.

3:30 Jit proposes a “Type-C I/O”

4:00 Thunderbolt already allows displayport to tunnel through it

4:30 Thunderbolt already has a combination of capabilities. It has a display mode – you can buy a Thunderbolt display. This means you can run data and display using the same technology

6:30 There’s a notion of a muxed signals

7:00 The PHY speed is the most important. Thunderbolt is running 20 Gb/s

7:15 What would the physical connection look like? Will the existing USB Type-C interface work? Currently we already see 80 Gb/s ports (4 lanes) in existing consumer PCs

9:20 Daniel hates charging his phone without fast charging

9:40 The USB protocol is for data transfer, but is there going to be a future USB dispaly protocol? There are already some audio and video modes in current USB, like a PC headset

11:30 Why are we changing? The vision is to plug it in and have it “just work”

12:00 Today, standards groups are quite separate. They each have their own ecosystems that they are comfortable in. So, this is a big challenge for getting to a single spec

13:15 Performance capabilities, like cable loss, is also a concern and challenge

14:00 For a tech like this were to exist, will the groups have to merge? Or, will someone just come out with a spec that obsoletes all of the others?

15:30 Everyone has a cable hoard. Daniel’s is a drawer, Mike’s is a shoebox

16:30 You still have to be aware of the USB Type-C cables that you buy. There’s room for improvement

17:30 Mike wants a world of only USB Type-C connectors and 3.5mm headphone jacks

18:30 From a test and measurement perspective, it’s very attractive to have a single protocol. You’d only have to test at one rate, one time

19:30 Stupid questions

USB 3.2 + Why You Only Have USB Ports On One Side of Your Laptop – #32

USB 3.2 DOUBLES the data transfer capabilities of previous USB specifications, and could mean the end of having USB ports on just one side of your computer. Find out more in today’s electrical engineering podcast with Jit Lim, Daniel Bogdanoff, and Mike Hoffman.

USB 3.2 DOUBLES the data transfer capabilities of previous USB specifications, and could mean the end of having USB ports on just one side of your computer. Find out more in today’s electrical engineering podcast with Jit Lim, Daniel Bogdanoff, and Mike Hoffman.

 

1:00
Jit is the USB and Thunderbolt lead for Keysight.

1:30
USB 3.2 specifications were released Fall 2017 and released two main capabilities.

USB 3.2 doubles the performance of  USB 3.1. You can now run 10Gb/s x2. It uses both sides of the CC connector.

In the x2 mode, both sides of the connectors are used instead of just one.

4:00
The other new part of USB 3.2 is that it adds the ability to have the USB silicon farther away from the port. It achieves this using retimers, which makes up for the lossy transmission channel.

5:00
Why laptops only have USB ports on one side! The USB silicon has to be close to the connector.

6:30
If the silicon is 5 or 6 inches away from the connector, it will fail the compliance tests. That’s why we need retimers.

7:15
USB is very good at maintaining backwards compatibility

The USB 3.0 spec and the USB 3.1 spec no longer exist. It’s only USB 3.2.

The USB 3.2 specification includes the 3.0 and the 3.1 specs as part of them, and acts as a special mode.

9:00
From a protocol layer and a PHY layer, nothing much has changed. It simply adds communication abilities.

9:55
Who is driving the USB spec? There’s a lot of demand! USB Type C is very popular for VR and AR.

12:00
There’s no benefit to using legacy devices with modern USB 3.2 ports.

13:45
There’s a newly released variant of USB Type C that does not have USB 2.0 support. It repurposes the USB 2 pins. It won’t be called USB, but it’ll essentially be the same thing. It’s used for a new headset.

15:20
USB Type C is hugely popular for VR and AR applications. You can send data, video feeds, and power.

17:00
Richie’s Vive has an audio cable, a power cable, and an HDMI cable. The new version, though, has a USB Type-C that handles some of this.

18:00
USB 3.2 will be able to put a retimer on a cable as well. You can put one at each end.

What is a retimer? A retimer is used when a signal traverses a lossy board or transmission line. A retimer acquires the signal, recovers it, and retransmits it.

It’s a type of repeater. Repeaters can be either redrivers or repeaters. A redriver just re-amplifies a signal, including any noise. A retimer does a full data recovery and re-transmission.

21:20
Stupid Questions:
What is your favorite alt mode, and why?
If you could rename Type-C to anything, what would you call it?

 

 

 

Memory, DDR5+, and JEDEC – #24

“It’s a miracle it works at all.” In this electrical engineering podcast, we discuss the state of memory today and it’s inevitable march into the future.

Hosted by Daniel Bogdanoff and Mike Hoffman, EEs Talk Tech is a twice-monthly engineering podcast discussing tech trends and industry news from an electrical engineer’s perspective.

“It’s a miracle it works at all.” Not the most inspiring words from someone who helped define the latest DDR spec. But, that’s the the state of today’s memory systems. Closed eyes and mV voltage swings are the topic of today’s electrical engineering podcast. Daniel Bogdanoff (@Keysight_Daniel) and Mike Hoffman sit down with Perry Keller to talk about the state of memory today and it’s inevitable march into the future.

Agenda:

00:00 Today’s guest is Perry Keller, he works a lot with standards committees and making next generation technology happen.

00:50 Perry has been working with memory for 15 years.

1:10 He also did ASIC design, project management for software and hardware

1:25
Perry is on the JEDEC board of directors

JEDEC is one of the oldest standards body, maybe older than IEEE

1:50 JEDEC was established to create standards for semiconductors. This was an era when vacuum tubes were being replaced by solid state devices.

2:00 JEDEC started by working on instruction set standards

2:15 There are two main groups. A wide bandgap semiconductors group and a memory group.

3:00 Volatile memory vs. nonvolatile memory. An SSD is nonvolatile storage, like in a phone. But if you look at a DIMM in a PC that’s volatile.

3:40 Nonvolatile memory is everywhere, even in light bulbs.

4:00 Even a DRAM can hold its contents for quite some time. JEDEC had discussions about doing massive erases because spooks will try to recover data from it.

DRAM uses capacitors for storage, so the colder they are the longer they hold their charge.

4:45 DRAM is the last vestige of the classical wide single ended parallel bus. “It’s a miracle that it works at all.”

5:30 Perry showed a friend a GDDR5 bus and challenged him to get an eye on it and he couldn’t.

6:10 Even though DDR signals look awful, it depends on reliable data transfer. The timing and clocking is set up in a way to deal with all of the various factors.

7:00 DDR specifications continue to march forward. There’s always something going on in memory.

8:00 Perry got involved with JEDEC through a conversation with the board chairman.

8:35 When DDR started, 144 MT/s (megatransfers per second) was considered fast. But, DDR5 has and end of life goal of 6.5 GT/s on a 80+ bit wide single ended parallel bus.

9:05 What are the big drivers for memory technology? Power. Power is everything. LPDDR – low power DDR – is a big push right now.

9:30 if you look at the memory ecosystem, the big activity is in mobile. The server applications are becoming focused with the cloud, but the new technology and investment is mobile.

10:00 If you look at a DRAM, you can divide it into three major categories. Mainstream PC memory, low power memory, and GDDR. GDDR is graphics memory. The differences are in both power and cost.

For example, LPDDR is static designs. You can clock it down to DC, which you can’t do with normal DDR.

The first DDR was essentially TTL compatible. Now, we’re looking at 1.1V power supplies and voltage swings in the mV.

Semiconductor technology is driving the voltages down to a large degree.

11:45 DRAM and GDDR is a big deal for servers.

A company from China tried to get JEDEC to increase the operating temperature range of DRAMs by 10 C. They fire up one new coal fired power plant per week in China to meet growing demand. They found they could cut it down to only 3 per month with this change in temperature specs.

13:10 About 5 years ago, the industry realized that simply increasing I/O speeds wouldn’t help system performance that much because the core memory access time hasn’t changed in 15 years. The I/O rate has increased, but basically they do that by pulling more bits at once out of the core and shifting them out. The latency is what really hurts at a system level.

14:15 Development teams say that their entire budget for designing silicon is paid for out of smaller electric bills.

15:00 Wide bandgap semiconductors are happy running at very high temperatures. If these temperatures end up in the data centers, you’ll have to have moon suits to access the servers.

16:30 Perry says there’s more interesting stuff going on in the computing than he’s seen in his whole career.

The interface between different levels is not very smooth. The magic in a spin-up disk is in the cache-optimizing algorithms. That whole 8-level structure is being re-thought.

18:00 Von Neumann architectures are not constraining people any more.

18:10 Anything that happens architecturally in the computing world affects and is affected by memory.

22:10 When we move from packaged semiconductors to 3D silicon we will see the end of DDR. The first successful step is called high bandwidth memory, which is essentially a replacement for GDDR5.

23:00 To move to a new DDR spec, you basically have to double the burst size.

Data Analytics for Engineering Projects – #23

Learn some best practices for engineering projects that have huge amounts of data. Data analytics tools are crucial for project success! Listen in on today’s EEs Talk Tech electrical engineering podcast.

It seems most large labs have a go-to data person. You know, the one who had to upgrade his PC so it could handle insanely complex Excel pivot tables? In large electrical engineering R&D labs, measurement data can often be inaccessible and unreliable.

In today’s electrical engineering podcast, Daniel Bogdanoff (@Keysight_Daniel) sits down with Ailee Grumbine and Brad Doerr to talk about techniques for managing test & measurement data for large engineering projects.

 

Agenda:

1:10 – Who is using data analytics?

2:00 – for a hobbyist in the garage, they may still have a lot of data. But, because it’s a one-person team, it’s much easier to handle the data.

Medium and large size teams generate a lot of data. There are a lot of prototypes, tests, etc.

3:25 – The best teams manage their data efficiently. They are able to make quick, informed decisions.

4:25 – A manager told Brad, “I would rather re-make the measurements because I don’t trust the data that we have.”

6:00 – Separate the properties from the measurements. Separate the data from the metadata. Separating data from production lines, prototype units, etc. helps us at Keysight make good engineering decisions.

9:30 – Data analytics helps for analyzing simulation data before tape out of a chip.

10:30 – It’s common to have multiple IT people managing a specific project.

11:00 – Engineering companies should use a data analytics tool that is data and domain agnostic.

11:45 – Many teams have an engineer or two that manage data for their teams. Often, it’s the team lead. They often get buried in data analytics instead of engineering and analysis work. It’s a bad investment to have engineers doing IT work.

14:00 – A lot of high speed serial standards have workshops and plugfests. They test their products to make sure they are interoperable and how they stack up against their competitors.

15:30 – We plan to capture industry-wide data and let people see how their project stacks up against the industry as a whole.

16:45 – On the design side, it’s important to see how the design team’s simulation results stack up against the validation team’s empirical results.

18:00 – Data analytics is crucial for manufacturing. About 10% of our R&D tests make it to manufacturing. And, manufacturing has a different set of data and metrics.

19:00 – Do people get hired/fired based on data? In one situation, there was a lack of data being shared that ended up costing the company over $1M and 6 months of time-to-market.

 

 

 

Power Integrity and Signal Integrity – Electrical Engineering Podcast #19

Learn about power integrity and signal integrity in this electrical engineering podcast. Power integrity will impact signal integrity, EMI, and EMC! We sit down with Kenny Johnson to discuss.

Hosted by Daniel Bogdanoff and Mike Hoffman, EEs Talk Tech is a twice-monthly engineering podcast discussing tech trends and industry news from an electrical engineer’s perspective.

How’s the impedance of your ground plane? Do you look at your power rails in the frequency domain? Mike Hoffman and Daniel Bogdanoff sit down with power integrity expert Kenny Johnson to discuss the latest trends and techniques for measuring power supplies in today’s electrical engineering podcast.

00:15 Kenny gave us a tip during scope month

01:26 There are two types of power people.

There are power producers, like the wind farms, power plants, and AC/DC adapter creators

There are power consumers, who care very much about their power quality. The ripple on power supplies, etc.

3:03 Power integrity is the study of the effectiveness of the conversion and delivery of DC power from the source to the gates on the IC.

3:45 If Moore’s Law holds out for another 600 years, we will have a computer that is capable of simulating every atom in the known universe.

4:35 Thermal hotspots were causing problems, so voltage levels started dropping

5:00 Kenny went to Amazon to look for a power integrity book. There were only 2-3 books a few years ago

Power integrity has been a thing since the 1930s

5:50 Product functional reliability is directly proportional to the power quality in a product.

We’re supplying a voltage to devices, but also current. So, this starts to look a lot like Ohm’s law.

A device has both power and a ground plane.

Power integrity pioneers include Istvan Novak and Ray Ridley and they talk about flat impedance power planes.

7:15 Flat impedance power planes – divide the supply power by the peak current, multiply it by your tolerance, you get a target impedance for your power planes.

If you can maintain a frequency flat impedance, you don’t see noise on your power supplies.

7:55 Think back to circuits 101, an inductor is open at a high frequency. And, a power plane is basically a big inductor. If you are, for example, writing high speed digital data to memory, it will be a problem.

8:40 When you look at boards, you see bypass capacitors to counteract the inductors

10:30 Experienced engineers use a lot of intuition when working out power distribution. Now, there’s a lot of localized power distribution.

11:15 A typical SSD has 12 power supplies

A tablet can have 50 power supplies

Some of our oscilloscopes have 180 power supply rails

Next generation mobile electronics 100-200 power supplies

12:25 There are redundant power supplies spread out across the device to help improve reliability. For example, there may be multiple converters that all power the same rail to help spread the loads.

The reason intuition is used is that a lot of people don’t have access to good simulation tools. They just have to use some rules of thumb and over-engineer the device to try to get reliability.

15:10 Kenny has a lot of patents. Our CTO Jay Alexander used to hold the record for most patents at the Colorado Springs site. Kenny has nearly 30 patents.

17:15 Kenny started as a probe designer, then got into power integrity.

Kenny recommends one by Bogatin about signal integrity, and a second edition called Signal Integrity and Power Integrity

18:35 SIPI labs – signal integrity and power integrity lab. Power integrity will affect your signal integrity, your EMI (electromagnetic interference) and your EMC (electromagnetic compatibility). (measure power integrity with a power rail probe)

So, the progressive companies have these SIPI labs. There are more advanced tools available.

20:10 Multiple papers say that power supply induced jitter is the single biggest source of data jitter in a digital system.

Kenny has some IOT development kits, and it’s easy to make them drop bits. Dropping bits will have an effect on battery life, performance, etc.

21:08 How to clean up a power supply? The majority of the time, it’s easiest to use a bypass capacitor. After you’ve looked at your supply in the time domain, look at it in the frequency domain. That will help you debug where the noise is coming from. And, if you know the frequency you are having trouble with, you can work backward into a bypass capacitor

22:42 There are some general rules that seem to apply to everything in electronics. Closer to the device is always better.

Next podcast – wide bandgap! The US Department of Energy will pay for some people to go back to university and get a degree in power engineering. Wide bandgap semiconductors have a huge potential to reduce energy usage.

 

PAM4 and 400G – Ethernet #18

Learn how PAM4 is allowing some companies to double their data rate – and the new challenges this brings up for engineers. (electrical engineering podcast)

Today’s systems simply can’t communicate any faster. Learn how some companies are getting creative and doubling their data rates using PAM4 – and the extra challenge this technology means for engineers.

Mike Hoffman and Daniel Bogdanoff sit down with PAM4 transmitter expert Alex Bailes and PAM4 receiver expert Steve Reinhold to discuss the trends, challenges, and rewards of this technology.

 

1:00
PAM isn’t just cooking spray.

What is PAM4? PAM stands for Pulse Amplitude Modulation, and is a serial data communication technique in which more than one bit of data can be communicated per clock cycle. Instead of just a high (1) or low (0) value, a in PAM4, a voltage level can represent 00, 01, 10, or 11. NRZ is essentially just PAM2.

We are reaching the limit of NRZ communication capabilities over the current communication channels.

2:10 PAM has been around for a while, it was used in 1000BASE-T. 10GBASE-T uses PAM16, which means it has 16 different possible voltage levels per clock cycle. It acts a bit like an analog to digital converter.

2:55 Many existing PAM4 specifications have voltage swings of 600-800 mV

3:15 What does a PAM4 receiver look like?  A basic NRZ receiver just needs a comparator, but what about multiple levels?

3:40 Engineers add multiple slicers and do post-processing to clean up the data or put an ADC at the receiver and do the data analysis all at once.

PAM4 communicates 2-bits per clock cycle, 00, 01, 10, or 11.

4:25 Radio engineers have been searching for better modulation techniques for some time, but now digital people are starting to get interested.

4:40 With communications going so fast, the channel bandwidth limits the ability to transmit data.

PAM4 allows you to effectively double your data rate by doubling the amount of data per clock cycle.

5:05 What’s the downside of PAM4? The Signal to Noise Ratio (SNR) for PAM4  worse than traditional NRZ. In a perfect world, the ideal SNR would be 9.6 dB (for four levels instead of two). In reality, it’s worse, though.

5:30 Each eye may not be the same height, so that also has an effect on the total SNR.

6:05 What’s the bit error ratio (BER) of a PAM4 vs. NRZ signal if the transmission channel doesn’t change?

6:45 The channels were already challenged, even for many NRZ signals. So, it doesn’t look good for PAM4 signals. Something has to change.

7:00 PAM4 is designed to operate at a high BER. NRZ typically specified a 1E-12 or 1E-15 BER, but many PAM4 specs are targeting 1E-4 or 1E-5. It uses forward error correction (or other schemes) to get accurate data transmission.

7:50 Companies are designing more complex receivers and more robust computing power to make PAM4 work. This investment is worth it because they don’t have to significantly change their existing hardware.

8:45 PAM is being driven largely by Ethernet. The goal is to get to a 1 Tb/s data rate.

9:15 Currently 400 GbE is the next step towards the 1 Tbps Ethernet rate (terabit per second).

10:25 In Steve’s HP days, the salesmen would e-mail large pictures (1 MB) to him to try to fill up his drive.

11:10 Is there a diminishing rate of return for going to higher PAM levels?

PAM3 is used in automotive Ethernet, and 1000BASE-T uses PAM5.

Broadcom pushed the development of PAM3. The goal was to have just one pair of cables going through a vehicle instead of the 4 pairs in typical Ethernet cables.

Cars are an electrically noisy environment, so Ethernet is very popular for entertainment systems and less critical systems.

Essentially, Ethernet is replacing FlexRay. There was a technology battle for different automotive communication techniques. You wouldn’t want your ABS running on Ethernet because it’s not very robust.

14:45 In optical communication systems there is more modulation, but those systems don’t have the same noise constraints.

For digital communications, PAM8 is not possible over today’s channels because of the noise.

15:20 PAM4 is the main new scheme for digital communications

15:50 Baseband digital data transmission covers a wide frequency range. It goes from DC (all zeroes or all ones) to a frequency of the baud rate over 2 (e.g. 101010). This causes intersymbol interference (ISI) jitter that has to be corrected for – which is why we use transmitter equalization and receiver equalization.

16:55 PAM4 also requires clock recovery, and it is much harder to recover a clock when you have multiple possible signal levels.

17:35 ISI is easier to think about on an NRZ signal. If a signal has ten 0s in a row, then transitions up to ten 1s in a row,  the channel attenuation will be minimal. But, if you put a transition every bit, the attenuation will be much worse.

19:15 To reduce ISI, we use de-emphasis or pre-emphasis on the transmit side, and equalization on the receiver side. Engineers essentially boost the high frequencies at the expense of the low frequencies. It’s very similar to Dolby audio.

20:40 How do you boost only the high frequencies? There are circuits you can design that react based on the history of the bit stream. At potentially error-inducing transition bits, this circuitry drives a higher amplitude than a normal bit.

22:35 Clock recovery is a big challenge, especially for collapsed eyes. In oscilloscopes, there are special techniques to recover the eye and allow system analysis.

With different tools, you can profile an impulse response and detect whether you need to de-emphasize or modify the signal before transmission. Essentially, you can get the transfer function of your link.

23:45 For Ethernet systems, there are usually three equalization taps. Chip designers can modify the tap coefficients to tweak their systems and get the chip to operate properly. They have to design in enough compensation flexibility to make the communication system operate properly.

25:00 PAM vs. QAM? Is QAM just an RF and optical technique, or can it be used in a digital system?

25:40 Steve suspects QAM will start to be used for digital communications instead of just being used in coherent communication systems.

26:30 PAM4 is mostly applicable to the 200 GbE and 400 GbE, and something has to have to happen for us to get faster data transfer.

26:48 Many other technologies are starting to look into PAM4 – InfiniBand, Thunderbolt, and PCIe for example.

You can also read the EDN article on PAM4 here. If you’re working on PAM4, you can also check out how to prepare for PAM4 technology on this page.

 

 

 

 

Quantum Bits and Cracking RSA – #16

What does a quantum computer look like? What does the future of cyber security hold? We sit down with Lee Barford to discuss.

Hosted by Daniel Bogdanoff and Mike Hoffman, EEs Talk Tech is a twice-monthly engineering podcast discussing tech trends and industry news from an electrical engineer’s perspective

 

How will quantum computing change the future of security? What does a quantum computer look like? Mike and Daniel sit down with Lee Barford to get some answers.

Video Version:

Audio version

Last time we looked at “what is quantum computing” and talked about quantum bits and storing data in superstates.

00:40 Lee talks about how to crack RSA and Shor’s algorithm (wikipedia)

00:50 The history of quantum computing (wiki). The first person to propose it was Richard Feynman in the mid 1960s. There was some interest, but it died out.

In the 1990s, Peter Shor published a paper pointing out that if you could build a quantum computer with certain operational properties (machine code instructions), then you could find one factor of a number no matter how long it is.

Then, he outlined another number of things he would need, like a quantum Fast Fourier Transform (FFT).

Much of the security we use every day is both the RSA public key system and the Diffie Hellman Key Exchange algorithm.

HTTPS connections use the Diffie Hellman Key Exchange algorithm. RSA stands for “really secure algorithm” “Rivest, Shamir, and Adelman.”

4:00

RSA only works if the recipients know each other, but Diffie Hellman works for people who don’t know each other but still want to communicate securely. This is useful because it’s not practical for everyone to have their own RSA keys.

5:00

Factoring numbers that are made up of large prime numbers is the basis for RSA. The processing power required for factoring is too large to be practical. People have been working on this for 2500 years.

6:45

Shor’s algorithm is theoretically fast enough to break RSA. If you could build a quantum computer with enough quantum bits and operate with a machine language cycle time that is reasonable (us or ms), then it would be possible to factor thousand bit numbers.

7:50

Famous professors and famous universities have a huge disparity of opinion as to when a quantum computer of that size could be built. Some say 5-10 years, others say up to 50.

8:45

What does a quantum computer look like? It’s easier to describe architecturally than physically. A quantum computer isn’t that much different from a classical computer, it’s simply a co-processor that has to co-exist with current forms of digital electronics.

9:15

If you look at Shor’s algorithm, there are a lot of familiar commands, like “if statements” and “for loops.” But, quantum gates, or quantum assembly language operations, are used in the quantum processor. (more about this)

10:00

Lee thinks that because a quantum gate operates in time instead of space, the term “gate” isn’t a great name.

10:30

What quantum computers exist today? Some have been built, but with only a few quantum bits. The current claim is that people have created quantum computers with up to 21 quantum bits. But, there are potentially a lot of errors and noise. For example, can they actually maintain a proper setup and hold time?

11:50

Continuing the Schrodinger’s Cat analogy…

In reality, if you have a piece of physics that you’ve managed to put into a superimposed quantum state, any disturbance of it (photon impact, etc.) will cause it to collapse into an unwanted state or to collapse too early.

13:15

So, quantum bits have to be highly isolated from their environments. So, in vacuums or extreme cold temperatures (well below 1 degree Kelvin!).

13:45

The research companies making big claims about the quantity of bits are not using solid state quantum computers.

The isolation of a quantum computer can’t be perfect, so there’s a limited lifetime for the computation before the probability of getting an error gets too high.

14:35

Why do we need a superposition of states? Why does it matter when the superimposed states collapse to one state? If it collapses at the wrong time you’ll get a wrong answer. With Shor’s algorithm it’s easy to check for the right answer. And, you get either a remainder of 0 or your don’t. If you get 0, the answer is correct. The computation only has to be reliable enough for you to check the answer.

16:15

If the probability of getting the right answer is high enough, you can afford to get the wrong answer on occasion.

16:50

The probability of the state of a quantum bit isn’t just 50%, so how do you set the probability of the state? It depends on the physical system. You can write to a quantum bit by injecting energy into the system, for example using a very small number of photons as a pulse with a carefully controlled timing and phase.

18:15

Keysight helps quantum computer researchers generate and measure pulses with metrological levels of precision.

The pulses have to be very carefully timed and correlated with sub nanosecond accuracy. You need time synchronization between all the bits at once for it to be useful.

19:40

What is a quantum bit? Two common kinds of quantum bits are

1: Ions trapped in a vacuum with laser trapping . The ions can’t move because they are held in place by standing waves of laser beams. The vacuum can be at room temperature but the ions are low temperature because they can’t move.

2. Josephson junctions in tank circuits (a coil capacitor) produce oscillations at microwave frequencies. Under the right physical conditions, those can be designed to behave like an abstract two state quantum system. You just designate zero and one to different states of the system.

Probabilities are actually a wrong description, it should be complex quantum amplitudes.

23:00

Josephson junctions were talked about in an earlier electrical engineering podcast discussing SI units.

23:40

After working with quantum computing, it’s common to walk away feeling a lot less knowledgeable.

24:30

Stupid question section:

“If you had Schrodinger’s cat in a box, would you look or not?”

Lee says the cat’s wave function really collapsed as it started to warm up so the state has already been determined.

 

 

What is Quantum Computing?- #15

Learn about the basics of quantum computing and quantum computers from Dr. Lee Barford. We discuss Schrodinger’s cat and more!

Hosted by Daniel Bogdanoff and Mike Hoffman, EEs Talk Tech is a twice-monthlyelectrical engineering podcast discussing tech trends and industry news from an electrical engineer’s perspective.

What is a quantum computer and what is quantum computing? In this week’s episode, Daniel Bogdanoff and Mike Hoffman are joined by quantum computing expert Lee Barford.

Video Version (YouTube):

Audio Only:

0:45 Intro

Lee Barford helps to guide Keysight into the quantum computing business + enables the quantum computing experts at Keysight

 

2:00 The importance of quantum computing

Clock rates in all types of digital processors stopped going up in 2006 due to heating limits

The processor manufacturers realized the need for more parallelism.

Today, Lee helps engineers at Keysight take advantage of this parallelism.

Graphics processors can be used as vector and matrix machines

Bitcoin utilizes this method.

 

6:00 The implications of advancements in quantum computing

Today, there are parts being made with feature size of the digital transistor that are 10, maybe 7 nanometers (depending on who you believe)

So we are heading below 5 nanometers, and there aren’t many unit cells of silicon left at that point. (a unit cell of silicon is 0.5 nanometer)

The uncertainty principle comes into play since there are few enough atoms where quantum mechanical effects will disturb the electronics.

There are many concerns including a superposition of states (Schrodinger’s cat) and low error tolerance.

 

10:20 Is Moore’s law going to fail? 

Quantum computing is one way of moving the computer industry past this barrier

Taking advantage of quantum mechanical effects, engineering with them, to build a new kind of computers that for certain problems, promise to do better than what we currently do.

 

15:20 Questions for future episodes:

What sort of technology goes into a quantum computer?

What’s the current state of experimentation?

What are some of the motivations for funding quantum computing research?

How is Keysight involved in this industry?

What problems is quantum computing aiming to solve?

 

17:30 Using quantum effects to our advantage

Quantum computers likely be used in consumer devices because there has to be a very low temperature and/or a vacuum.

18:00

A quantum computer’s fundamental storage unit is a qubit (quantum bit).  A quantum bit (qubit) can be either 1 or 0 with some finite probability

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A quantum register can store multiple qubits, and when read, have a probability of being either of these numbers. A quantum register can store more than one state at a time, but only one value can be read from the quantum register.

21:00 How does one get a useful value out of a quantum register? You do as much of the computation before reading the state and then read the quantum computers quantum register.

This works because the quantum computer’s either has such a high probability to be correct that you don’t need to verify it, or it’s simple to double check if the answer is correct.

21:00 How do you get the desired value out of a quantum register? You do as much of the computation ahead of time and then read the quantum computers quantum register.

22:30 Quantum computers can factor very large numbers (breaking RSA in cryptography)