# Maximum clock frequency ?

• posted

Hi Skybuck,

this is a VHDL discussion board ;o) And not a general information board ;o)

Rgds Andr=E9

• posted

The fastest transistor I've heard of operates at 604 GHz.

Cheers, Jon

• posted

I thought the Illinois university guys had obtained transistors operating at 1 Tera Hz .

• posted

Instead of asking all these painfully basic questions and getting one-off short answers, perhaps you should go shopping at your local bookstore or on the web for information on computer architecture? Trying to get 50,000 words worth of information from random newsgroup queries is like trying to build a house out of cut-off ends of 2x4 lumber -- and it makes us work at answering questions bit by bit that are better answered all at once (or at least in much larger chunks).

```--
Tim Wescott
Wescott Design Services```
• posted

Hi, ;)

I am beginning to understand how CPU's and chip like that work.

I think the clock frequency is very important.

It's almost like the hearbeat of the computer.

It determines how fast the signals change from zero to one and back.

And these signals are what drives the computer.

So I think a very important question would be:

What is the maximum frequency that these kind of "cpu clocks" can provide ?

Other components should ofcourse also be able to handle these high frequencies.

Like t_flipflops etc :)

So what's the best of the best at the moment ? ;)

Bye, Skybuck.

• posted

Remember also, that the clock frequency is only one 'part' of the equation giving what the system can do. It is effectively multiplied by the 'width' of the registers, when dealing with numerical values, and also may be multiplied internally using either a PLL, or short phase delays, so multiple operations are generated in each clock. you should really think about the clock, like the speedlimit on a road, with the width of the registers, being perhaps like the difference between a motorbike, and a bus, while the internal phase seqencing, acts like having multiple lanes of traffic running in parallel. In terms of the actual number of people the road can carry, you have to multiply all these differences together, but the clocking limits the minimum time a single person can take to transit part of the road. An internal PLL, acts like a local 'expressway', reducing this time.

Best Wishes

• posted

"Skybuck Flying" schrieb im Newsbeitrag news:dcnbgj\$8fr\$ snipped-for-privacy@news2.zwoll.ov.home.nl...

Hello Skybuck,

forget T-fliflops. This is the least important part of an IC-design. I know you read about it in a VHDL intro book, but they made this just as an example and not because it's important.

You should really look first for a FPGA design flow, e.g.

, ...,
After you understand that you can look for full costom ICs.

You can buy divider flipflops with 20GHz.

Best regards, Helmut

• posted

Ok so if this is my clock rate:

111111111111111000000000000000

Can the PLL divide it into:

1111111100000000111111100000000 ? ;)

or maybe even further into ;)

11110000111100001111000011110000 ? ;)

I think that's what it could do/does ?

So the PLL creates a faster clock rate inside the chip ?

Would this mean the "normal" clock is outside of the chip ?

How many real clocks or oscilators(=clock?;)) are there ?

Can the main memory chips and the cpu share the same clock ?

However a transistor is not a clock so my original question is not yet answered ? ;)

So what's the fastest clock on todays computers and say 5 years from now ?

For my one bit streaming cpu a PLL might not be interesting...

Since I was more thinking of having all the bits stream across/through/into/out of the cpu directly from main memory ;)

The question is if multiple bits can be transfered in serial over a single wire with a slower clock frequency and then still be processed by a cpu with a faster clock frequency... the cpu would have to buffer some bits I guess. Or something like that... maybe not possible ;) or maybe it would be possible with bursts.

However... since I don't like all this complexity... (and I dont like bursts too ;)) I am wondering if my simple cpu will need a clock at all ;)

So just for the kick of it ;)

Can VHDL also be used to design/test circuitry without clocks in them ? ;)

Bye, Skybuck.

• posted

Actually, he is cross-trolling to comp.arch, comp.lang.vhdl, and sci.electronics.design, which is where I'm reading it.

--Mac

• posted

The fastest transistors seem to be carbon nanotubes, and IIRC, they go well above 1 THz. The main problem to get real figures is probably the unsuitable equipment to measure these things. In theory, a carbon nanotube oscillator should be able to drive a 300nm carbon nanotube dipole, emitting blue light (now that would be something that's not that hard to measure).

```--
Bernd Paysan
"If you want it done right, you have to do it yourself"```
• posted

In addition, learning to use a search engine and finding out how to narrow a search has an instructive quality all its own.

Here's the one for the sci.electronics.* part of the Usenet Archives:

• posted

While one should not in general feed the trolls as a matter of principle, I will make an exception just to point out that your question suggests you have not really thought about the problem in any depth.

What matters most for real circuit design is not the highest frequency that the clock can generate -- but rather how far can the clock signal be propagated reliably and without excessive distortion (distance and fan-out).

dk

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Is something we are all beginning to wish you would take more seriously.

• posted

provide ?

I am getting a error:

" Server Error The server encountered an error and could not complete your request. If the problem persists, please report your problem and mention this error message and the query that caused it. "

Maybe only a temporarely problem.

I still haven't seen any answer to my question... ;)

What's the maximum frequency nowadays ?

Bye, Skybuck.

• posted

"Skybuck Flying" schrieb im Newsbeitrag news:dd1mh0\$9bo\$ snipped-for-privacy@news4.zwoll.ov.home.nl...

Hello Skybuck,

you should see a dozen answers to your question if not then try another news group reader.

Again, You can achieve 20GHz(20e9Hz) with a T-fliflop.

Other insist they can get 100Tflop. Now I know why you wanted a design with T(flip)flop. Maybe this "flip" doubles the Tflop. :)

Sorry, I couldn't resist.

A simple processor alone could achieve some GHz, e.g. 10GHz, but it becomes very expensive and anotrher problem is feeding such a beast with enough data from memory. This is then something for an IEEE paper, but nothing which will make you rich.

Best regards, Helmut

• posted

Yesssss but maybe the propagation length doesn't matter for a small circuit like my 1 bit cpu =D

So I would still like to know what the maximum frequency is ;)

And in case the circuit is bigger how do circuits nowadays propagate the clock signal reliably ;)

Bye, Skybuck ;)

• posted

For a single bit you can use your great-grandfather's pocket watch. It shouldn't make any difference.

dk

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Or maybe it does? But its up to you to find out.

There is no such thing. Or very close to no such thing, except possibly somewhere in UV/r?ntgen border area.

You should first use Google and then ask. Or will you only be sensible when skybucks^H^H^H^H^H^H^H^Hpigs fly?

```--
Sander

+++ Out of cheese error +++```
• posted

error

??

But a T-flipflop is not a clock ???

• posted

... we're back that 1-bit Turing machine again ...

Maybe this thread is a real live Turing test? :)

```--
--------------------------------------+------------------------------------
Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/```

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