how to make a counter/timer circuit for 35GHz

[[email protected]]

Hi,All


As is well known, digital design is very easy to make a low-frequency
16-bit circuits. But now I have a square wave working at 35GHz, how
can I make an appropriate counter to measure this signal.btw,
resolution of ps(-1) is okey.


thanks!

 

[Tim Wescott]

Hi,All


As is well known, digital design is very easy to make a low-frequency
16-bit circuits. But now I have a square wave working at 35GHz, how
can I make an appropriate counter to measure this signal.btw,
resolution of ps(-1) is okey.


thanks!

If it's fairly narrowband the standard thing to do is to heterodyne it
down to something more reasonable and count that.

For instance, if you have a signal that varies between 33 & 37GHz you
can mix it with 32GHz and run it into a counter that can take 5GHz. You
should be able to get all the bits from Agilent.

Of course if it's sometimes 35GHz and sometimes nothing at all then
you're stuck needing something fast...

 

[John Woodgate]

I read in sci.electronics.design that [email protected] <[email protected]>

But now I have a square wave working at 35GHz

How do you know? You need a minimum bandwidth of 180 GHz to even
approximate a square wave at 35 GHz. With negligible phase shift.

 

[John Woodgate]

I read in sci.electronics.design that Tim Wescott
com>) about 'how to make a counter/timer circuit for 35GHz', on Sat, 2
Oct 2004:

If it's fairly narrowband the standard thing to do is to heterodyne it
down to something more reasonable and count that.

A narrow-band square wave I'd very much like to see. (;-)

 

[CBarn24050]

Subject: how to make a counter/timer circuit for 35GHz

From: [email protected] ([email protected])
Date: 03/10/2004 00:17 GMT Standard Time
Message-id: <[email protected]>

Hi,All


As is well known, digital design is very easy to make a low-frequency
16-bit circuits. But now I have a square wave working at 35GHz, how
can I make an appropriate counter to measure this signal.btw,
resolution of ps(-1) is okey.


thanks!

Hi, if you can produce a 35GHz squarewave you allready know far more then
anyone else on this usernet. maybe you could educate us and explain how you did
it.

 

[Tim Wescott]

I read in sci.electronics.design that Tim Wescott
com>) about 'how to make a counter/timer circuit for 35GHz', on Sat, 2
Oct 2004:



A narrow-band square wave I'd very much like to see. (;-)

OK, bad choice of wording.

* If it doesn't change frequency by more than a few GHz
* If it isn't amplitude modulated by more than 50% or so
* If it doesn't start and stop (see "change frequency")

then it will act as if it were a narrowband sine wave (etc.)

There, happy?

 

[Ken Smith]

[...]
A few ideas to extend Tim's suggestions:

* If it doesn't change frequency by more than a few GHz

If you make the hetrodyne part of a PLL, you can even have largish changes
and follow them. The tricky bit is making sure that the right frequency
from the frequency multiplier is the one mixing in.

* If it isn't amplitude modulated by more than 50% or so

So long as the modulation is not near the IF frequency it can be a
moderatley large.

* If it doesn't start and stop (see "change frequency")

This one is the hardest one to avoid trouble with. If the signal is keyed
on and off, the PLL method can still be used.

There, happy?

I am and that all that matters isn't it?

 

[John Larkin]

I read in sci.electronics.design that Tim Wescott
com>) about 'how to make a counter/timer circuit for 35GHz', on Sat, 2
Oct 2004:

A narrow-band square wave I'd very much like to see. (;-)

A 35 GHz square wave is what I want to see!

John

 

[John Woodgate]

I read in sci.electronics.design that Tim Wescott
com>) about 'how to make a counter/timer circuit for 35GHz', on Sun, 3
Oct 2004:

There, happy?

No, but it's not your fault. Clients, you know.

 

[[email protected]]

ahaha, I am not kidding you guys.
But, this is an idea I suddenly got!
the original story is once I knew that infrared range-measurement
working by measuring the vertical displacement in the linear CCD, why
not just count the time between transmitting and receiving!
I do some simply maths and post this question!
interesting, heh~~~

 

[Tim Shoppa]

ahaha, I am not kidding you guys.
But, this is an idea I suddenly got!
the original story is once I knew that infrared range-measurement
working by measuring the vertical displacement in the linear CCD, why
not just count the time between transmitting and receiving!
I do some simply maths and post this question!

Time-of-flight is a powerful method. But as you've found out, just
counting clock ticks is hard above a few GHz. ECL and fast CMOS
processes don't yet get to the 35GHz rate that you want to count at.
Since you're talking about 35GHz I assume that you want 30 picosecond
resolution.

Many commercial products for time-of-flight use TAC's (Time-to-amplitude
converters, a physics time-of-flight term) and then use an ADC after
that. Some techniques use TAC's as interpolators on a slower (but very
low jitter) counter. Other techniques just use TAC's with no need for
a counter.

Tim.

 

[Bill Sloman]

ahaha, I am not kidding you guys.
But, this is an idea I suddenly got!
the original story is once I knew that infrared range-measurement
working by measuring the vertical displacement in the linear CCD, why
not just count the time between transmitting and receiving!
I do some simply maths and post this question!
interesting, heh~~~

Do a google search on tellurometer.

A much more elegant way of measuring the time delay, which could be
made to work when 50MHz counters were the fastest things you could lay
hands on.

I'm afraid you've just tried to re-invent a very primitive form of the
wheel.