Your very own high-speed pattern generator

Can't afford a new Agilent series 81141A high-speed pattern generator, at only $101,673 starting price? My local rep writes to say that a refurbished N4901B, the older model capable of 13.5GB/s, costs $32k, or $54k for full BERT (not JBERT?), but only if ordered by Feb 28th. Call ASAP to reserve a unit, he says.

Reply to
Winfield Hill
Loading thread data ...

What sort of speed, patterns, and levels do you need?

The newish SRS clock box with the PRBS option ain't bad for $3K new. We just got one, and it's interesting. It's a 2 GHz box, but they limited the prbs to 1.55 GHz, presumably because the EclipsPlus shift register dies somewhere below 2G. The layout is cute, seven SO-8 flipflops in a circle with an xor gate off to the side, like a frying pan with a handle. It would go faster if they did the xor some other way.

I've got it running over the weekend into an infinite-persistance sampling scope to see if there are any outliers in the eye diagram.

I wonder if there's a market for a small pattern generator. It shouldn't be really hard up to, say, 5 GHz.

John

Reply to
John Larkin

What is JBERT?

Reply to
EE123

Being what J stands for for TI packages it's DILBERT.

--
Thanks,
Fred.
Reply to
Fred Bartoli

Some FPGAs come with high speed serial ports and an option to bypass the 8b/10b or 64b/66b encoders. If your pattern fits in the on chip ROMs, it should be straightforward to emit an arbitrary pattern at 10 G bits/sec. (I haven't done it, but it sounds like fun.)

--
These are my opinions, not necessarily my employer\'s.  I hate spam.
Reply to
Hal Murray

Design your own SiGe chip ? Unfortunately the chip fabs that do custom chips stick to CMOS. Configurable CMOS that is. If you had to pay for the photo masks yourself, one for each layer, you'd spend a fortune just on them.

Rene

--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
Reply to
Rene Tschaggelar

No, just use a fast FPGA to make patterns at 400 MHz or so, and mux up its outputs with some fast ECL, all stock parts. As someone noted, many of the high-end fpga's already do gigabit serial streams, but I don't know if they are general enough to be used directly as a pattern generator.

Yesterday we were, independently, brainstorming a box that would accept a customer trigger and generate some number of arbitrary digital and analog outputs, with picosecond jitter and resolution on all the output edges. We might do it if things slow down a little. We occasionally get an inquiry for stuff like this.

John

Reply to
John Larkin

I'd certainly like a 2**32-1 prbs generator that would go at least 5 Gb/s and would drive a telecom modulator (+24 dBm). Faster would be better, but 5 Gb/s would definitely be worth buying if it were under, say, $20k.

Cheers,

Phil Hobbs

PS: Now who would have suspected that Winfield Hill would stoop to FS spamming SED? ;)

Reply to
Phil Hobbs

That's do-able. Some GigaComm logic plus moderate dirty tricks could make the sequence, and then a couple of the Hittite 20 GHz distributed amps to drive your e-o modulator to 5-6 volts p-p. $1500 worth of parts maybe.

Shocked, shocked.

John

Reply to
John Larkin

I was trying to make a joke - tongue in cheek, hey, who who can afford $32 or 54k for a pulse generator, let alone $101k? Sheesh! The email I received from Agilent's rep was unsolicited, and filled with excitement for this special deal we'd jump at, but would disappear by the 28th.

Reply to
Winfield

Here's an idea I should save for a patent or perhaps it is too loony for even that:

There are materials with non-linear optical properties that could be used to cause a laser beam to deflect back and forth at a rate near the GHz range. Rubidium vapor in the one I am thinking about right now but there are some doped crystals that also would do this.

Two such devices at right angles could direct a Laser beam in a circle. This circle would strike a light switching device such as an LCD with a great many segments in a ring.

A bit of non-imaging optics could bring the light down to one location or put it onto a fiber. A lot of light would be lots in the process so the Laser will have to be modestly powerful.

At this point, if enough segments are in the light switch, you can have light that is switching at a great many GHz.

Reply to
MooseFET

I've recently bought a couple of 40 Gb/s modulators (30 GHz 3 dB BW) from Avanex for about $6k each. That's about as fast as I need to go for the foreseeable future. They're about 70% efficient optically, but need about +24 dBm worth of drive.

Cheers,

Phil Hobbs

Reply to
Phil Hobbs

Me too. Agilent FS spam was too funny to miss.

Cheers,

Phil Hobbs

Reply to
Phil Hobbs

This is why high tech companies should never hire people who've sold used cars. :(

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
 Click to see the full signature
Reply to
Michael A. Terrell

At what frequency?

Reply to
Winfield

Why? Because they'd be too embarrassed to take the job?

--
Keith
Reply to
krw

They're only about 1 dB down at 20 GHz, iirc. At that sort of speed, the phase nonlinearity is at least as important as the rolloff.

Cheers,

Phil Hobbs

Reply to
Phil Hobbs

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.