signal indicator

[Cursitor Doom]

On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

> This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets blacker the
higher in frequency you go. Best avoided!



--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

On Thursday, May 2, 2019 at 11:15:28 PM UTC-4, John Larkin wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?

You could unbalance the pulldown loading on that buffer by 10-20% and detect that. Differential drive are the original wideband rectifier.

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Jeroen Belleman]

On 2019-05-04 14:41, Cursitor Doom wrote:

On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets blacker the
higher in frequency you go. Best avoided!

I'd hesitate to call a simple diode detector 'RF'. It's
about as simple as it gets. But why is RF a black art?
Logic and even opamps are so fast these days that they
work well into the RF domain.

Jeroen Belleman

 

[Joerg]

On 2019-05-03 08:18, John Larkin wrote:

On Fri, 3 May 2019 06:41:33 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

On 2019-05-03, John Larkin <jjlarkin@highlandtechnology.com> wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?

maybe use transistors instead of diodes?

Yes. BFT25 maybe, 5 GHz Ft.

Probably an ordinary BFS17 would also do. RC series in front of the
base, base at near zero DC via another resistive path. The BE junction
rectifies some and then an LED in the collector path is lit. Very little
base current will do because modern LED in the collector path at 1mA can
generate light that is uncomfortably bright. It'll pulse but very fast.

It is not very elegant but less parts.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Sat, 04 May 2019 07:03:47 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-05-03 08:18, John Larkin wrote:
On Fri, 3 May 2019 06:41:33 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

On 2019-05-03, John Larkin <jjlarkin@highlandtechnology.com> wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?

maybe use transistors instead of diodes?

Yes. BFT25 maybe, 5 GHz Ft.


Probably an ordinary BFS17 would also do. RC series in front of the
base, base at near zero DC via another resistive path. The BE junction
rectifies some and then an LED in the collector path is lit. Very little
base current will do because modern LED in the collector path at 1mA can
generate light that is uncomfortably bright. It'll pulse but very fast.

It is not very elegant but less parts.

BFS17 is great precisely because it's fast but not too fast. But
probably a tad slow to detect 2 GHz. Ft is just about 2 GHz.

The dual doubler thing looks good, from a few hundred KHz to over 2
GHz, with 5 pF loading on each side of my diff ECL logic.

https://www.dropbox.com/s/axonmf82uzxhpyi/Sig_Indicator_2.JPG?dl=0

If I use a Hittite HMC987 fanout chip, I can use one of its diff ECL
outputs just for the monitor LED, and I can load that as hard as I
like.

https://www.dropbox.com/s/avw42lia7ejayug/Sig_Indicator_3.JPG?dl=0

That Hittite chip is $20.




--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Joerg]

On 2019-05-04 07:39, Jeroen Belleman wrote:

On 2019-05-04 14:41, Cursitor Doom wrote:
On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets blacker the
higher in frequency you go. Best avoided!

I'd hesitate to call a simple diode detector 'RF'. It's
about as simple as it gets. But why is RF a black art?

It isn't. It's fun. Whenever I do RF at a client that is about the only
time where I really regret getting older and retiring. There is so much
to do and it seems the next generations aren't supplying enough
engineers for this field.

Logic and even opamps are so fast these days that they
work well into the RF domain.

Yeah, but "real men's RF" is discrete. Just like real cars have a
clutch. Which I was really happy to have on a drive in the mountains
yesterday.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-05-03 08:26, John Larkin wrote:

On Fri, 3 May 2019 04:50:31 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 5/2/19 11:15 PM, John Larkin wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?



Looks OK to me--you might not need detectors in both leads.

Cheers

Phil Hobbs

I thought the symmetry was pleasing, with equal loading on each logic
line. I guess I have lots of signal, by RF standards, so one zero-bias
detector should work fine.

Even one diode should work.

Skyworks has nice sampling diodes, also of the cheaper kind. Pick an LED
with low Vf and it could work. Some are really bright with just a
fraction of a mA. Just keep in mind that some fast diodes can go PHUT
when you exceed a couple of volts reverse by too much.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Sat, 04 May 2019 08:23:10 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-05-03 08:26, John Larkin wrote:
On Fri, 3 May 2019 04:50:31 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 5/2/19 11:15 PM, John Larkin wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?



Looks OK to me--you might not need detectors in both leads.

Cheers

Phil Hobbs

I thought the symmetry was pleasing, with equal loading on each logic
line. I guess I have lots of signal, by RF standards, so one zero-bias
detector should work fine.

Even one diode should work.


Skyworks has nice sampling diodes, also of the cheaper kind. Pick an LED
with low Vf and it could work. Some are really bright with just a
fraction of a mA. Just keep in mind that some fast diodes can go PHUT
when you exceed a couple of volts reverse by too much.

I like their SMS7621. It's rated 2 volts reverse but it doesn't leak
much until about 5.

I don't mind a schottky detector and than a comparator or opamp to
drive the LED.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Sat, 04 May 2019 08:27:53 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-05-04 07:39, Jeroen Belleman wrote:
On 2019-05-04 14:41, Cursitor Doom wrote:
On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets blacker the
higher in frequency you go. Best avoided!

I'd hesitate to call a simple diode detector 'RF'. It's
about as simple as it gets. But why is RF a black art?


It isn't. It's fun. Whenever I do RF at a client that is about the only
time where I really regret getting older and retiring. There is so much
to do and it seems the next generations aren't supplying enough
engineers for this field.


Logic and even opamps are so fast these days that they
work well into the RF domain.


Yeah, but "real men's RF" is discrete. Just like real cars have a
clutch. Which I was really happy to have on a drive in the mountains
yesterday.

I work in time domain, picoseconds some times, but I don't think
that's RF. RF, to me, is LC-tuned narrowband circuits and antennas.
DC-to-10 GHz is more macho than 9.9 to 10.1 GHz.

My Audi is the first automatic I've ever owned, and I think manuals
are silly now. The 6-speed dual-clutch tranny is faster and smarter
than I am, and it's great on the hills here. I can manual shift it if
I want, and occasionally do for engine braking, like on the crazy
downhill after Donner Summit, where grannies in SUVs (and truck
drivers) are smoking their brakes.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Cursitor Doom]

On Sat, 04 May 2019 08:27:53 -0700, Joerg wrote:

> Yeah, but "real men's RF" is discrete.

Exactly. Conquering all those instabilities, strays and parasitics
fearlessly head-on. Not suitable for wimmin or gays.



--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[John Larkin]

On Sat, 4 May 2019 16:35:04 -0000 (UTC), Cursitor Doom
<curd@notformail.com> wrote:

On Sat, 04 May 2019 08:27:53 -0700, Joerg wrote:

Yeah, but "real men's RF" is discrete.

Exactly. Conquering all those instabilities, strays and parasitics
fearlessly head-on. Not suitable for wimmin or gays.

I know lots of Real Men who are afraid of the p-word: picosecond.

Some are even afraid of the n-word.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[whit3rd]

On Saturday, May 4, 2019 at 6:22:54 AM UTC-7, bloggs.fre...@gmail.com wrote:

On Thursday, May 2, 2019 at 11:15:28 PM UTC-4, John Larkin wrote:
I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz.
I'd like to light an LED if there is signal present.

You could unbalance the pulldown loading on that buffer by 10-20% and detect that. Differential drive are the original wideband rectifier.

Good plan, but that mainly detects duty cycle unless the load is frequency-dependent.
And, over a thousand-to-one range of frequencies, at that. Am I being
unreasonable in wanting to get an indication of amplitude or frequency from a detector?

An oldschool plan: two termination resistors, one capacitor-coupled. Thermal-couple both resistors
to diodes, and detect any difference in forward drop on the diodes. The only RF components
are resistors and a blocking capacitor to reject DC. A humble LM324 jellybean can handle
the fine details of driving an LED.

Box it up with a couple of penlight cells, and you have a low-Z RF probe.

 

[Jeroen Belleman]

On 2019-05-04 17:59, John Larkin wrote:

On Sat, 04 May 2019 08:27:53 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-04 07:39, Jeroen Belleman wrote:
On 2019-05-04 14:41, Cursitor Doom wrote:
On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets blacker the
higher in frequency you go. Best avoided!

I'd hesitate to call a simple diode detector 'RF'. It's
about as simple as it gets. But why is RF a black art?


It isn't. It's fun. Whenever I do RF at a client that is about the only
time where I really regret getting older and retiring. There is so much
to do and it seems the next generations aren't supplying enough
engineers for this field.


Logic and even opamps are so fast these days that they
work well into the RF domain.


Yeah, but "real men's RF" is discrete. Just like real cars have a
clutch. Which I was really happy to have on a drive in the mountains
yesterday.

I work in time domain, picoseconds some times, but I don't think
that's RF. RF, to me, is LC-tuned narrowband circuits and antennas.
DC-to-10 GHz is more macho than 9.9 to 10.1 GHz.
[...]

Agreed. I'm envious sometimes of our RF colleagues who can
'tune out' some parasitic capacitance or other, or noise-match
some amplifier to sub-1dB noise figures, with just a simple L-C
network, while I'm struggling with wide-band analogues of the
same, much harder, yet also much more interesting.

Jeroen Belleman

 

[Joerg]

On 2019-05-04 08:41, John Larkin wrote:

On Sat, 04 May 2019 08:23:10 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-03 08:26, John Larkin wrote:
On Fri, 3 May 2019 04:50:31 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 5/2/19 11:15 PM, John Larkin wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?



Looks OK to me--you might not need detectors in both leads.

Cheers

Phil Hobbs

I thought the symmetry was pleasing, with equal loading on each logic
line. I guess I have lots of signal, by RF standards, so one zero-bias
detector should work fine.

Even one diode should work.


Skyworks has nice sampling diodes, also of the cheaper kind. Pick an LED
with low Vf and it could work. Some are really bright with just a
fraction of a mA. Just keep in mind that some fast diodes can go PHUT
when you exceed a couple of volts reverse by too much.

I like their SMS7621. It's rated 2 volts reverse but it doesn't leak
much until about 5.

That is also one of my favorites. I found that when you push them past
3-4V they "aren't always the same" afterwards. Some sort of damage
happens but it isn't necessarily a full failure.

I don't mind a schottky detector and than a comparator or opamp to
drive the LED.

That should work nicely but I'd try a transistor just for sports.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-05-04 08:31, John Larkin wrote:

On Sat, 04 May 2019 07:03:47 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-03 08:18, John Larkin wrote:
On Fri, 3 May 2019 06:41:33 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

On 2019-05-03, John Larkin <jjlarkin@highlandtechnology.com> wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?

maybe use transistors instead of diodes?

Yes. BFT25 maybe, 5 GHz Ft.


Probably an ordinary BFS17 would also do. RC series in front of the
base, base at near zero DC via another resistive path. The BE junction
rectifies some and then an LED in the collector path is lit. Very little
base current will do because modern LED in the collector path at 1mA can
generate light that is uncomfortably bright. It'll pulse but very fast.

It is not very elegant but less parts.

BFS17 is great precisely because it's fast but not too fast. But
probably a tad slow to detect 2 GHz. Ft is just about 2 GHz.

That's ok, you aren't relying on it being a perfect amplifier. Only to
have the BE junction rectify a little and cause enough CE current to
keep an LED lit. The LED won't see much of the RF. In essence the same
that happens in EMI cases but where this isn't desired, where cell phone
RF >1GHz rectifies itself at the first BE junction of even slow opamps
and causes a demodulated signal in the output.

The dual doubler thing looks good, from a few hundred KHz to over 2
GHz, with 5 pF loading on each side of my diff ECL logic.

https://www.dropbox.com/s/axonmf82uzxhpyi/Sig_Indicator_2.JPG?dl=0

Nice but that's a lot of parts.

If I use a Hittite HMC987 fanout chip, I can use one of its diff ECL
outputs just for the monitor LED, and I can load that as hard as I
like.

https://www.dropbox.com/s/avw42lia7ejayug/Sig_Indicator_3.JPG?dl=0

That Hittite chip is $20.

Ouch!

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-05-04 08:59, John Larkin wrote:

On Sat, 04 May 2019 08:27:53 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-04 07:39, Jeroen Belleman wrote:
On 2019-05-04 14:41, Cursitor Doom wrote:
On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets blacker the
higher in frequency you go. Best avoided!

I'd hesitate to call a simple diode detector 'RF'. It's
about as simple as it gets. But why is RF a black art?


It isn't. It's fun. Whenever I do RF at a client that is about the only
time where I really regret getting older and retiring. There is so much
to do and it seems the next generations aren't supplying enough
engineers for this field.


Logic and even opamps are so fast these days that they
work well into the RF domain.


Yeah, but "real men's RF" is discrete. Just like real cars have a
clutch. Which I was really happy to have on a drive in the mountains
yesterday.

I work in time domain, picoseconds some times, but I don't think
that's RF. RF, to me, is LC-tuned narrowband circuits and antennas.
DC-to-10 GHz is more macho than 9.9 to 10.1 GHz.

Time domain is usually harder and it's real RF. TDR, for example, where
you can get weird kinds of reflections and you have to understand and
diagnosed where they could be coming from. A slight connector or via
mismatch may not even show up in a 10GHz narrowband circuit but in
pulse-echo it can cause a lot of frustration.

My Audi is the first automatic I've ever owned, and I think manuals
are silly now. The 6-speed dual-clutch tranny is faster and smarter
than I am, and it's great on the hills here. I can manual shift it if
I want, and occasionally do for engine braking, like on the crazy
downhill after Donner Summit, where grannies in SUVs (and truck
drivers) are smoking their brakes.

I drove a rental car like that in Germany and it's ok. 7-speed automatic
when the stick was pulled towards one side, hand-shifting when pushed to
the other side, no clutch pedal. I still don't want it on ice, snow or
in mud. Or when you have to rock the car out of a nasty diagonal rut
with shifting rocks in there.

When I later rented a stick-shift box truck with clutch and all I was
surprised nobody came out to the truck with me despite my California
license. Maybe they thought if someone can speak German he knows how to
drive those.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Cursitor Doom]

On Sat, 04 May 2019 10:39:14 -0700, John Larkin wrote:

On Sat, 4 May 2019 16:35:04 -0000 (UTC), Cursitor Doom
curd@notformail.com> wrote:

On Sat, 04 May 2019 08:27:53 -0700, Joerg wrote:

Yeah, but "real men's RF" is discrete.

Exactly. Conquering all those instabilities, strays and parasitics
fearlessly head-on. Not suitable for wimmin or gays.

I know lots of Real Men who are afraid of the p-word: picosecond.

Some are even afraid of the n-word.

Nanosecond. I saw what you did there!



--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[John Larkin]

On Sat, 04 May 2019 12:13:26 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-05-04 08:31, John Larkin wrote:
On Sat, 04 May 2019 07:03:47 -0700, Joerg <news@analogconsultants.com
wrote:

On 2019-05-03 08:18, John Larkin wrote:
On Fri, 3 May 2019 06:41:33 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

On 2019-05-03, John Larkin <jjlarkin@highlandtechnology.com> wrote:

I'll have a LVDS signal with data or a square wave, in the range of
maybe 1 MHz to 2 GHz. I figure I can pump it through an 10EP89 ECL
buffer to give it some heft. Each output will become almost 2 volts
p-p.

I'd like to light an LED if there is signal present. How does this
look?

https://www.dropbox.com/s/bvyjs4zgyprx3tu/Sig_Indicator.JPG?dl=0

The 10 pF caps shouldn't load my signals much, especially in the lower
signal path that doesn't need to be super fast.

I suppose I could buy some fancy RF detector chip, but I'd rather just
use fairly ordinary parts.

Any other ideas?

maybe use transistors instead of diodes?

Yes. BFT25 maybe, 5 GHz Ft.


Probably an ordinary BFS17 would also do. RC series in front of the
base, base at near zero DC via another resistive path. The BE junction
rectifies some and then an LED in the collector path is lit. Very little
base current will do because modern LED in the collector path at 1mA can
generate light that is uncomfortably bright. It'll pulse but very fast.

It is not very elegant but less parts.

BFS17 is great precisely because it's fast but not too fast. But
probably a tad slow to detect 2 GHz. Ft is just about 2 GHz.


That's ok, you aren't relying on it being a perfect amplifier. Only to
have the BE junction rectify a little and cause enough CE current to
keep an LED lit. The LED won't see much of the RF. In essence the same
that happens in EMI cases but where this isn't desired, where cell phone
RF >1GHz rectifies itself at the first BE junction of even slow opamps
and causes a demodulated signal in the output.


The dual doubler thing looks good, from a few hundred KHz to over 2
GHz, with 5 pF loading on each side of my diff ECL logic.

https://www.dropbox.com/s/axonmf82uzxhpyi/Sig_Indicator_2.JPG?dl=0


Nice but that's a lot of parts.

With ECL swings, about 800 mV p-p, it works better with fewer diodes:

https://www.dropbox.com/s/xndruojyp819042/Sig_Indicator_4.JPG?dl=0

Then an opamp to drive the LED.

If I use a Hittite HMC987 fanout chip, I can use one of its diff ECL
outputs just for the monitor LED, and I can load that as hard as I
like.

https://www.dropbox.com/s/avw42lia7ejayug/Sig_Indicator_3.JPG?dl=0

That Hittite chip is $20.


Ouch!

It's wonderful. If it helps me sell a bunch of $1500 boxes, it's a
bargain. The CML comparator ahead of it costs almost as much.

We're looking at some distributed amplifier chips in the $200-400
range, and some fast logic gates for $70 each.




--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Phil Hobbs]

On 2019-05-04 08:59, John Larkin wrote:

On Sat, 04 May 2019 08:27:53 -0700, Joerg
news@analogconsultants.com> wrote:

On 2019-05-04 07:39, Jeroen Belleman wrote:
On 2019-05-04 14:41, Cursitor Doom wrote:
On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets
blacker the higher in frequency you go. Best avoided!

I'd hesitate to call a simple diode detector 'RF'. It's about as
simple as it gets. But why is RF a black art?


It isn't. It's fun. Whenever I do RF at a client that is about the
only time where I really regret getting older and retiring. There
is so much to do and it seems the next generations aren't supplying
enough engineers for this field.


Logic and even opamps are so fast these days that they work well
into the RF domain.


Yeah, but "real men's RF" is discrete. Just like real cars have a
clutch. Which I was really happy to have on a drive in the
mountains yesterday.

I work in time domain, picoseconds some times, but I don't think
that's RF. RF, to me, is LC-tuned narrowband circuits and antennas.
DC-to-10 GHz is more macho than 9.9 to 10.1 GHz.

Time domain is usually harder and it's real RF. TDR, for example, where
you can get weird kinds of reflections and you have to understand and
diagnosed where they could be coming from. A slight connector or via
mismatch may not even show up in a 10GHz narrowband circuit but in
pulse-echo it can cause a lot of frustration.

My Audi is the first automatic I've ever owned, and I think manuals
are silly now. The 6-speed dual-clutch tranny is faster and smarter
than I am, and it's great on the hills here. I can manual shift it
if I want, and occasionally do for engine braking, like on the crazy
downhill after Donner Summit, where grannies in SUVs (and truck
drivers) are smoking their brakes.

I drove a rental car like that in Germany and it's ok. 7-speed automatic
when the stick was pulled towards one side, hand-shifting when pushed to
the other side, no clutch pedal. I still don't want it on ice, snow or
in mud. Or when you have to rock the car out of a nasty diagonal rut
with shifting rocks in there.

When I later rented a stick-shift box truck with clutch and all I was
surprised nobody came out to the truck with me despite my California
license. Maybe they thought if someone can speak German he knows how to
drive those.

Cars and computers should do as they're damn well told. I drive a 2012
Mustang convertible that I bought new in 2017. (It got snagged in the
Takata air bag recall.)

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

On 2019-05-04 19:51, Phil Hobbs wrote:

On 5/4/19 11:27 AM, Joerg wrote:
On 2019-05-04 07:39, Jeroen Belleman wrote:
On 2019-05-04 14:41, Cursitor Doom wrote:
On Fri, 03 May 2019 11:30:58 -0700, John Larkin wrote:

This is RF, and I don't do RF!

Can't say I blame you. It's a bit of a black art which gets blacker the
higher in frequency you go. Best avoided!

I'd hesitate to call a simple diode detector 'RF'. It's
about as simple as it gets. But why is RF a black art?


It isn't. It's fun. Whenever I do RF at a client that is about the
only time where I really regret getting older and retiring.

So don't. Beer you can buy.

However, you can't buy the fitness that a full day of mountain biking
brings. Like I did on Friday. You just can't get that at a gym. I have
seen enough people who worked into the 70's, never had time for this
sports stuff and then paid a heavy price via a failing body. Assisted
living many years earlier than usual. This doesn't only apply to members
of the "0.1-ton class". I know people who are wiry and thin yet I can
see the effects of not doing any long endurance activities. The folks
that start huffing after a couple of briskly walked miles with hills in
there.

The other thing is volunteer work, in my case lay caregiving for our
church and, privately, nursing home visits. That kind of activity only
works with strict and pretty full schedules which would interfere with
consulting.

Also, bought beer isn't as good as homebrew almost no matter how
expensive. Not even close. So now I only take on some hardcore work,
enticing clients to hire their own engineers of finding another
consultant and then jumping in when they become stuck. Keeps the brain
cells going, creates income and retains a dose of EE fun for me.

--
Regards, Joerg

http://www.analogconsultants.com/