very accurate timer

Resolution is cheap; jitter is expensive. So you get lots of resolution!

John

Was lucky to pick the SL6440 as mixer #1 in a spectrum analyser I built 20 years ago. Naively thought all Gilbert cell type mixers would offer similar performance. Sadly not so, as I discovered years later, having to use a LM1496 in lieu of the obsoleted 6440. Great chip!. ISTR something like a + 40dBm TOI but do remember it had a rabid thirst for DC current. john

--
Posted via a free Usenet account from http://www.teranews.com

Hello John,

3rd order is more like +30dBm but even that is a heck of a lot. And yes, it needs a whopping 50mA or so.

IMHO some of their other chips were not as good but I was surprised that the rights to the 6440 masks weren't sold to a company that would continue to produce it. In their days Plessey lacked in one crucial area and that was advertising. Mini-Ciruits always had that nailed and so every analog engineer knew them. When I built a prototype ultrasound Doppler frontend with the 6440 for a group to show what a FET mixer could do it blew them away. They hadn't heard of Plessey until then and that did not surprise me. In the end we did it in discretes because the longevity of the Plessey line had become a bit uncertain. In hindsight I was glad we did.

What else do you think was leading to the downfall of Plessey? Did they ride cushy defense contracts too much?

--
Regards, Joerg

http://www.analogconsultants.com

On 13 Oct 2006 11:06:19 -0700, snipped-for-privacy@ieee.org wrote in Msg.

It's wire, but not coax. (ALPHA 2844/19-1000)

Doesn't turn up anything.

Don't have the printed catalogue. In fact I stopped using Farnell when they stopped sending me their catalogue because their website (just as RS's) is damn near unusable. Never bothered to ask them to send me a catalogue again though.

robert

Do you want it? I can email it to you (623 kB).

--Daniel

You must have cut and pasted the wrong number - a simple search on

157284 on their "unusable" web-site produced the page

including the line (apart from the "55dB per 100metres" which I added from the catalogue.

"CABLE, COAX 50 VMTX 100M; Impedance:50R; Conductor make-up:1/0.17mm; Diameter, External:1.17mm; Material, conductor:Copper plated Steel; Material, primary insulation:PTFE; Coaxial cable type:50VMTX; Attenuation, 100 MHz: 55dB per 100metres."

Your loss.

--
Bill Sloman, Nijmegen

On 16 Oct 2006 02:44:16 -0700, snipped-for-privacy@ieee.org wrote in Msg.

OK, here's "my" search on 157284 (without the dash, my previous result was with dash):

Thick Film Resistor Series:CRCW; Resistance:2.8kOhm; Resistance Tolerance:+/- 1 %; Power Rating:0.1W; Voltage Rating:75V; Temperature Coefficient:+/-100 ppm; Package/Case:0603; Leaded Process Compatib

42K3772

But the reason now is clear: You use the UK site, I use the German one. On the UK site I indeed found the cable which, sadly, isn't nearly as miniature as I had hoped (I need more like .6mm, PTFE insulated).

So the Farnell website gives different results depending on the presence of a dash in the order code and the language flavor of their site. So much for "unusable".

Thanks for the link anyway.

robert

What's wrong with the Farnell website? I don't know about browsing (I use the excellent catalog for that), but type in a part number and up comes all the details, direct PDF datasheet links (none of that stupid popup java rubbish), current stock etc - perfect.

Dave :)

Hello Daniel

Yes, that would be nice. I always like reading historic EE papers. Either use the de-munged address or jsc at analogconsultants. But only if it doesn't take much time to find the file.

--
Regards, Joerg

http://www.analogconsultants.com

Joerg wrote: [...]

That was the ostensible reason. The real one was their accountants and the UK obsession with short term returns. Essentially the bean counters couldn't be arsed working for their profits. Last company I worked at had a 1 year turn round on cap' ex'. If really tasty returns were expected then they'd maybe stretch to a whopping 18 months!. Plessey was a crying shame as they had some superb products. Still enjoy dipping into their 1/4 century old radio and radar app' handbooks. Yes. Why can't more of these orphaned classic silicon designs be picked up and run with by enterprising companies?.

2N3866 VHF power transistors. These were obsoleted ages ago but I'm told the reason I can still buy them, is a specialist company picked up the design and batches a few thousand every few months.

up an old i.c. design and remanufacture. Kind of like the aftermarket for classic cars and motorbikes. Specialist and nichey but if the IC's chosen with care, maybe profitable

john

Hello John,

I've seen that as well. In the US the usual time span is one quarter. The quarter numbers have to look good, else nothing matters anymore.

It's tough. You could probably run it fabless if they didn't pull fancy tricks with the process and then have it produced on an old 4" or 5" line. But what is there other than the SL6440 and a few transistors that would have market volume? Thing is, most young lads can't design with this stuff anymore. There are a lot of "Lego engineers" out there today. They need it all in a few chips with just traces in between, and an SPI port. The minute a tapped inductor pops up in the application schematic they freak out.

--
Regards, Joerg

http://www.analogconsultants.com

This is odd. I do use the U.K. web-site for browing - I find it easier to read English than Dutch - but I've got an account with Farnell in the Netherlands, and get the Benelux copy of the Farnell catalogue, with all the prices in euro's.

I had thought that the Farnell catalogue was pretty much the same - give or take the price information - all around the world. When Farnell took over Newark, some years ago, Winfield Hill got a U.S. Farnell catalogue that was essentially identical to the Duch version, and the Australian and New Zealand version seems to be much the same as well.

We live and learn.

--
Bill Sloman, Nijmegen

They would really have freaked out over the silver on glass spiral tapped inductors Microdyne used. ;-)

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

It took only seconds. It's on the way.

--Daniel

Hello Daniel,

Got it. Thanks, Daniel.

--
Regards, Joerg

http://www.analogconsultants.com