signal indicator

J

John Larkin

Guest
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?


--

John Larkin Highland Technology, Inc

lunatic fringe electronics
 
John Larkin <jjlarkin@highlandtechnology.com> wrote in
news:qpbnce5sutommh6bp15932fvrkkdv8eans@4ax.com:

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

That should drive it fine. At 2V I am sure you won't have any false
threshold read issues.
 
On Fri, 3 May 2019 03:18:19 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

John Larkin <jjlarkin@highlandtechnology.com> wrote in
news:qpbnce5sutommh6bp15932fvrkkdv8eans@4ax.com:

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

That should drive it fine. At 2V I am sure you won't have any false
threshold read issues.
Click to expand...

I suppose I could clock a 1 into an ECL flipflop, and clear the flop
at, say, 1 KHz. The flop would drive the LED. That's a more 'official'
design, a bit more expensive maybe.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics
 
On Thursday, May 2, 2019 at 8:15:28 PM UTC-7, 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.
Click to expand...

What I've done (not knowing the duty cycle of a signal pulse)
is toggle a flipflop. On anything regular, that makes a 50%
duty cycle square wave.

Flipflops have true/invert outputs, so a capacitor-resistor limiter
into a back-to-back LED pair makes indicator that only lights up when
there's logic transitions.

<https://www.digikey.com/schemeit/project/sync-blinker-EG6GCCG00220/>

This one was battery-powered, sensing a TTL pulse.
 
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?
Click to expand...

maybe use transistors instead of diodes?



--
When I tried casting out nines I made a hash of it.
 
On 03/05/2019 04:15, 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?
Click to expand...
You could measure the current taken by the buffer. Well, you did say
'any other ideas'.

Cheers
--
Clive
 
On Friday, 3 May 2019 04:15:28 UTC+1, 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?
Click to expand...

just add Rs in series with your 10pF pickoffs.

Oh, you can also simplify it if you don't mind it missing a single transition one way only. Signal thru C, R to ground, through R into tr. Add collector led/r. Job done.


NT
 
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?
Click to expand...

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

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On 03/05/2019 4:15 am, 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?
Click to expand...

Just two NPNs might be enough:

<https://www.dropbox.com/s/ykjyjcbb0jjuon1/JLsigInd.jpg?dl=0>

piglet
 
John Larkin wrote...
I suppose I could buy some fancy RF detector chip,
but I'd rather just use fairly ordinary parts.
Click to expand...

I think you should go with the detector chip.


--
Thanks,
- Win
 
On Fri, 3 May 2019 08:58:40 +0100, Clive Arthur
<cliveta@nowaytoday.co.uk> wrote:

On 03/05/2019 04:15, 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 measure the current taken by the buffer. Well, you did say
'any other ideas'.

Cheers
Click to expand...

ECL supply current is pretty much constant with frequency.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics
 
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
Click to expand...

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.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics
 
On 3 May 2019 03:43:08 -0700, Winfield Hill <hill@rowland.harvard.edu>
wrote:

John Larkin wrote...

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

I think you should go with the detector chip.
Click to expand...

They are not cheap. May as well use a flipflop, which we have in
stock.

https://www.dropbox.com/s/ieq1raaqyyn2oxi/Sig_Ind_6.JPG?dl=0

That would be zero risk and would work to arbitrarily low frequencies.
The ECL loading is entirely orthodox.

Adding a new part to the PADS library, and to stock, is a chore.

With 2 volts p-p on two lines, a diode detector should be safe too.

A BFT25 rectifying emitter follower would be interesting.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics
 
On Thu, 2 May 2019 22:51:11 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Thursday, May 2, 2019 at 8:15:28 PM UTC-7, 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.

What I've done (not knowing the duty cycle of a signal pulse)
is toggle a flipflop. On anything regular, that makes a 50%
duty cycle square wave.

Flipflops have true/invert outputs, so a capacitor-resistor limiter
into a back-to-back LED pair makes indicator that only lights up when
there's logic transitions.

https://www.digikey.com/schemeit/project/sync-blinker-EG6GCCG00220/

This one was battery-powered, sensing a TTL pulse.
Click to expand...

At 2 GHz, I'd need an ECL flipflop, and that only swings 0.8 volts.

With an ECL flop, this would work:

https://www.dropbox.com/s/ieq1raaqyyn2oxi/Sig_Ind_6.JPG?dl=0



--

John Larkin Highland Technology, Inc

lunatic fringe electronics
 
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?
Click to expand...

Yes. BFT25 maybe, 5 GHz Ft.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics
 
John Larkin wrote...
On 3 May 2019 03:43:08 -0700, Winfield Hill wrote:
John Larkin wrote...

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

I think you should go with the detector chip.

They are not cheap. May as well use a flipflop ...
Click to expand...

I'm OK with your flip flop idea, standard fast parts.
I was worried about up to 2GHz with ordinary diodes.


, which we have in
stock.

https://www.dropbox.com/s/ieq1raaqyyn2oxi/Sig_Ind_6.JPG?dl=0

That would be zero risk and would work to arbitrarily low frequencies.
The ECL loading is entirely orthodox.

Adding a new part to the PADS library, and to stock, is a chore.

With 2 volts p-p on two lines, a diode detector should be safe too.

A BFT25 rectifying emitter follower would be interesting.
Click to expand...

--
Thanks,
- Win
 
On 3 May 2019 09:55:36 -0700, Winfield Hill <hill@rowland.harvard.edu>
wrote:

John Larkin wrote...

On 3 May 2019 03:43:08 -0700, Winfield Hill wrote:
John Larkin wrote...

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

I think you should go with the detector chip.

They are not cheap. May as well use a flipflop ...

I'm OK with your flip flop idea, standard fast parts.
I was worried about up to 2GHz with ordinary diodes.
Click to expand...

We stock an SMS7621, which is a tiny 0.25 pF schottky. 16 cents each.

It's a low barrier part, and I have 2 volt swings so it should be OK
as a zero-bias detector or doubler.

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

Hey, maybe I could make a directional coupler or two out of PCB traces
instead of the capacitor pickoffs.




--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
John Larkin wrote...
Winfield Hill wrote:

I was worried about up to 2GHz with ordinary diodes.

We stock an SMS7621, which is a tiny 0.25 pF schottky.
16 cents each.
Click to expand...

I hope it's the SMS7621-079LF version, SC-79, 0.2pF.


--
Thanks,
- Win
 
On 3 May 2019 09:55:36 -0700, Winfield Hill <hill@rowland.harvard.edu>
wrote:

John Larkin wrote...

On 3 May 2019 03:43:08 -0700, Winfield Hill wrote:
John Larkin wrote...

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

I think you should go with the detector chip.

They are not cheap. May as well use a flipflop ...

I'm OK with your flip flop idea, standard fast parts.
I was worried about up to 2GHz with ordinary diodes.


, which we have in
stock.

https://www.dropbox.com/s/ieq1raaqyyn2oxi/Sig_Ind_6.JPG?dl=0

That would be zero risk and would work to arbitrarily low frequencies.
The ECL loading is entirely orthodox.

Adding a new part to the PADS library, and to stock, is a chore.

With 2 volts p-p on two lines, a diode detector should be safe too.

A BFT25 rectifying emitter follower would be interesting.
Click to expand...

This works surprisingly well, good output from 500 KHz to 2 GHz. C1
would be bigger in real life. There's just a 5 pF load on the ECL.

Version 4
SHEET 1 880 680
WIRE -304 96 -576 96
WIRE -80 128 -160 128
WIRE -16 128 -80 128
WIRE 96 128 48 128
WIRE 128 128 96 128
WIRE 208 128 128 128
WIRE 336 128 272 128
WIRE 480 128 336 128
WIRE 512 128 480 128
WIRE -304 160 -464 160
WIRE 336 160 336 128
WIRE 512 160 512 128
WIRE -576 176 -576 96
WIRE 128 176 128 128
WIRE -464 208 -464 160
WIRE 128 288 128 240
WIRE 336 288 336 240
WIRE 512 288 512 224
WIRE -576 320 -576 256
WIRE -464 320 -464 288
FLAG 128 288 0
FLAG 336 288 0
FLAG 512 288 0
FLAG -80 128 GEN
FLAG 480 128 OUT
FLAG 96 128 MID
FLAG -576 320 0
FLAG -464 320 0
SYMBOL diode 144 240 R180
WINDOW 0 -45 25 Left 2
WINDOW 3 -41 -4 Left 2
SYMATTR InstName D1
SYMATTR Value Ds
SYMBOL diode 208 144 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D2
SYMATTR Value Ds
SYMBOL res 320 144 R0
WINDOW 0 67 46 Left 2
WINDOW 3 49 78 Left 2
SYMATTR InstName R1
SYMATTR Value 100K
SYMBOL cap 496 160 R0
WINDOW 0 61 20 Left 2
WINDOW 3 53 57 Left 2
SYMATTR InstName C1
SYMATTR Value 50p
SYMBOL cap 48 112 R90
WINDOW 0 80 36 VBottom 2
WINDOW 3 87 32 VTop 2
SYMATTR InstName C2
SYMATTR Value 5p
SYMBOL SpecialFunctions\\modulate -304 96 R0
WINDOW 0 45 -55 Left 2
WINDOW 3 -46 -93 Left 2
SYMATTR InstName A1
SYMATTR Value mark=10Meg space=0
SYMBOL voltage -576 160 R0
WINDOW 0 -107 91 Left 2
WINDOW 3 -291 129 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 1 0 200u 0 1)
SYMBOL voltage -464 192 R0
WINDOW 0 71 38 Left 2
WINDOW 3 57 71 Left 2
SYMATTR InstName V1
SYMATTR Value 0.75
TEXT -336 352 Left 2 !.MODEL Ds D(IS=130n RS=4.5 N=1.08 XTI=1.8
EG=.68\n+ CJO=260f M=.047 VJ=.11 FC=.5 BV=4 IBV=10U TT=25p)
TEXT -208 280 Left 2 !.tran 100u
TEXT -16 -16 Left 2 ;SMS7621 Diode Detector
TEXT 48 24 Left 2 ;JL May 3 2019


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On 3 May 2019 13:09:25 -0700, Winfield Hill <hill@rowland.harvard.edu>
wrote:

John Larkin wrote...

Winfield Hill wrote:

I was worried about up to 2GHz with ordinary diodes.

We stock an SMS7621, which is a tiny 0.25 pF schottky.
16 cents each.

I hope it's the SMS7621-079LF version, SC-79, 0.2pF.
Click to expand...

We originally used the SC79, but they didn't solder well. Kept popping
off boards. Now we use the SOD323, aka BAT15-03W, about the same
capacitance.

I tried the 4-diode dual doubler and it works (in Spice) great.

Version 4
SHEET 1 880 680
WIRE 128 -128 80 -128
WIRE 160 -128 128 -128
WIRE 256 -128 224 -128
WIRE 304 -128 256 -128
WIRE 384 -128 304 -128
WIRE 512 -128 448 -128
WIRE 304 -80 304 -128
WIRE 80 -64 80 -128
WIRE 32 -48 -32 -48
WIRE 304 32 304 -16
WIRE 32 48 32 0
WIRE 80 48 80 16
WIRE 80 48 32 48
WIRE 80 80 80 48
WIRE -304 96 -576 96
WIRE -96 128 -160 128
WIRE -32 128 -32 -48
WIRE -32 128 -96 128
WIRE 160 128 -32 128
WIRE 256 128 224 128
WIRE 304 128 256 128
WIRE 384 128 304 128
WIRE 512 128 512 -128
WIRE 512 128 448 128
WIRE 624 128 512 128
WIRE 656 128 624 128
WIRE -304 160 -464 160
WIRE 512 160 512 128
WIRE 656 160 656 128
WIRE -576 176 -576 96
WIRE -464 176 -464 160
WIRE 304 176 304 128
WIRE 304 288 304 240
WIRE 512 288 512 240
WIRE 656 288 656 224
WIRE -576 320 -576 256
WIRE -464 320 -464 256
FLAG 304 288 0
FLAG 512 288 0
FLAG 656 288 0
FLAG -96 128 ECL+
FLAG 624 128 OUT
FLAG -576 320 0
FLAG -464 320 0
FLAG 304 32 0
FLAG 80 80 0
FLAG 256 -128 M1
FLAG 256 128 M2
FLAG 128 -128 ECL-
SYMBOL diode 320 240 R180
WINDOW 0 -45 25 Left 2
WINDOW 3 -41 -4 Left 2
SYMATTR InstName D1
SYMATTR Value Ds
SYMBOL diode 384 144 R270
WINDOW 0 -40 35 VTop 2
WINDOW 3 -46 32 VBottom 2
SYMATTR InstName D2
SYMATTR Value Ds
SYMBOL res 496 144 R0
WINDOW 0 60 46 Left 2
WINDOW 3 49 78 Left 2
SYMATTR InstName R1
SYMATTR Value 100K
SYMBOL cap 640 160 R0
WINDOW 0 61 20 Left 2
WINDOW 3 53 57 Left 2
SYMATTR InstName C1
SYMATTR Value 100p
SYMBOL cap 224 112 R90
WINDOW 0 80 31 VBottom 2
WINDOW 3 87 32 VTop 2
SYMATTR InstName C2
SYMATTR Value 5p
SYMBOL SpecialFunctions\\modulate -304 96 R0
WINDOW 0 45 -55 Left 2
WINDOW 3 -46 -93 Left 2
SYMATTR InstName A1
SYMATTR Value mark=10Meg space=0
SYMBOL voltage -576 160 R0
WINDOW 0 -93 89 Left 2
WINDOW 3 -280 129 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 1 0 200u 0 1)
SYMBOL voltage -464 160 R0
WINDOW 0 68 56 Left 2
WINDOW 3 54 88 Left 2
SYMATTR InstName V1
SYMATTR Value 0.75
SYMBOL diode 320 -16 R180
WINDOW 0 -45 25 Left 2
WINDOW 3 -41 -4 Left 2
SYMATTR InstName D3
SYMATTR Value Ds
SYMBOL diode 384 -112 R270
WINDOW 0 -40 39 VTop 2
WINDOW 3 -48 38 VBottom 2
SYMATTR InstName D4
SYMATTR Value Ds
SYMBOL cap 224 -144 R90
WINDOW 0 78 30 VBottom 2
WINDOW 3 87 32 VTop 2
SYMATTR InstName C3
SYMATTR Value 5p
SYMBOL e 80 -80 R0
WINDOW 0 32 92 Left 2
WINDOW 3 28 119 Left 2
SYMATTR InstName E1
SYMATTR Value -1
TEXT -400 320 Left 2 !.MODEL Ds D(IS=130n RS=4.5 N=1.08 XTI=1.8
EG=.68\n+ CJO=260f M=.047 VJ=.11 FC=.5 BV=4 IBV=10U TT=25p)
TEXT -600 24 Left 2 !.tran 100u
TEXT -712 -80 Left 2 ;SMS7621 Dual Doubler Detector
TEXT -624 -32 Left 2 ;JL May 3 2019

Gosh, this RF stuff is easy.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
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