On Mon, 07 Feb 2022 05:19:16 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:
>On a sunny day (Sun, 06 Feb 2022 15:06:15 -0800) it happened
>jlarkin@highlandsniptechnology.com wrote in
><2ok00hhf4nvrtvhap8oakeo98lpmcsodtq@4ax.com>:
>
>>A PCB transmission line oscillator would be OK, I guess.
>
>Probably.
>
>I am using the ADF4350 in some project,
>output frequency range: 137.5 MHz to 4400 MHz:
> http://panteltje.com/panteltje/newsflex/download.html#ADF4350_test
> has differential RF out,
>10 for 9$49 on ebay
>?
>
>complete evaluation board, I have it:
> https://www.ebay.com/itm/264492637509
>10 USD
>
>Chip needs some wires from your FPGA for programming though
>and some reference frequency around < 30MHz IIRC.
>
>
We use LMX2571, a really nice synthesizer. It only costs $7.50 but
it's kind of a big deal to use. We had to write the driver from
scratch and it was ugly. It wouldn't be so bad to program at one fixed
frequency, but would still need a uP or an FPGA and code. I just want
a tiny reasonably stable complementary 1.5 GHz clock.
The 10EP11 naturally oscillates at about 1.5G, with outputs connected
directly to inputs inverted, basically a prop delay oscillator. I
wonder if it can be persuaded to oscillate more predictably with an LC
tank in the loop. Maybe even above 1.5G.
--
I yam what I yam - Popeye
Reply by Anthony William Sloman●February 6, 20222022-02-06
On Monday, February 7, 2022 at 10:06:30 AM UTC+11, jla...@highlandsniptechnology.com wrote:
> On Sun, 06 Feb 2022 19:11:27 GMT, Jan Panteltje <pNaonSt...@yahoo.com> wrote:
> >On a sunny day (Sun, 06 Feb 2022 09:54:32 -0800) it happened John Larkin <jjla...@highlandtechnology.com> wrote in <sr9qvg5gc3rues8uv...@4ax.com>:
> >>On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje <pNaonSt...@yahoo.com> wrote:
> >>>On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin <jjla...@highlandtechnology.com> wrote in <l61ovg5sopebot77r...@4ax.com>:
<snip>
> >The twisted wire is cheaper :-)
>
> A PCB transmission line oscillator would be OK, I guess.
Jan wasn't exactly using a long length of twisted pair - it looked more like a capacitor than a delay line.
Twisted pair delay line is cheaper (in small quantities) than a purpose built PCB, an would probably work at 1.5GHz.
--
Bill Sloman, Sydney
Reply by whit3rd●February 6, 20222022-02-06
On Sunday, February 6, 2022 at 11:06:00 AM UTC-8, whit3rd wrote:
Oops; I just read the fine print; it only does 500 MHz with direct crystal input.
On the other hand, it has four outputs; you can combine them so the fundamental
is cancelled but the third harmonic is enhanced. Kinda like a tripler, but no tank
required, just resistors.
Reply by whit3rd●February 6, 20222022-02-06
On Sunday, February 6, 2022 at 2:59:56 PM UTC-8, jla...@highlandsniptechnology.com wrote:
> On Sun, 6 Feb 2022 11:05:53 -0800 (PST), whit3rd <whi...@gmail.com>
> wrote:
> >On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote:
> >
> >> We connected an MC10EP11 ...d it oscillates
> >> at 1.5 GHz with a fairly square wave out the 2nd diff pair.
> >>
> >> Tempco is mediocre. An LC would probably help. Given that I currently
> >> need a 1.5 GHz clock, doing this might be risky.
> >
> >Huh? What is wrong with temperature coefficient in this application?
> Huh?
Anything that oscillates that high probably has enough slew rate, and '1.5 GHz' usually
means between 1.45 and 1.55 is good enough. What, if any, criterion is in danger of thermal
drift out of compliance? Do you know that dependence isn't desirable? The target of this
clock surely has some temperature coefficients too.
Reply by ●February 6, 20222022-02-06
On Sun, 06 Feb 2022 19:11:27 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:
>On a sunny day (Sun, 06 Feb 2022 09:54:32 -0800) it happened John Larkin
><jjlarkin@highlandtechnology.com> wrote in
><sr9qvg5gc3rues8uvihhuop496q51dt7hv@4ax.com>:
>
>>On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje
>><pNaonStpealmtje@yahoo.com> wrote:
>>
>>>On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin
>>><jjlarkin@highlandtechnology.com> wrote in
>>><l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>:
>>>
>>>>I might do the oscillator with an ECL comparator, which gets me the
>>>>differential output. That could be RC, or LC.
>>>
>>>I have used the twisted wire oscillator, very stable too, tunable with a potmeter
>>>causing Vce changes that result in Ccb Cce changes etc:
>>> http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF
>>> http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG
>>>
>>>For lower frequencies the twisted part is longer,
>>>
>>>Chip specs may change. add that ECL to make differential output.
>>>There are probably a million types of oscillators, cavities come to mind too.
>>
>>We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
>>diff outout pair was cross-connected to the input, and it oscillates
>>at 1.5 GHz with a fairly square wave out the 2nd diff pair.
>>
>>Tempco is mediocre. An LC would probably help. Given that I currently
>>need a 1.5 GHz clock, doing this might be risky.
>>
>>We'll try a comparator next.
>>
>>I could buy a commercial VCO, but they are expensive.
>
>Yes
>I have some Sirenza VCOs
>vco190-1572t.pdf
> https://www.ebay.com/itm/402975121352 about 17 canadian $
> payed half that in 2013
Sirenza advertises GHz VCOs, but doesn't seem to want to sell tham in
smallish quantities. MiniCircuits does, but expensive.
>
>There is a cheaper one at about 1.5 GHz on ebay, dont know how good it is:
> https://www.ebay.com/itm/19141762235 about USD 8
>
>And I have a 960 MHz vco190-964t.pdf
Varil seems to be gone. I can't find them online.
>
>The twisted wire is cheaper :-)
A PCB transmission line oscillator would be OK, I guess.
--
I yam what I yam - Popeye
Reply by ●February 6, 20222022-02-06
On Sun, 6 Feb 2022 11:05:53 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:
>On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote:
>
>> We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
>> diff outout pair was cross-connected to the input, and it oscillates
>> at 1.5 GHz with a fairly square wave out the 2nd diff pair.
>>
>> Tempco is mediocre. An LC would probably help. Given that I currently
>> need a 1.5 GHz clock, doing this might be risky.
>
>Huh? What is wrong with temperature coefficient in this application?
Huh?
--
I yam what I yam - Popeye
Reply by Jan Panteltje●February 6, 20222022-02-06
On a sunny day (Sun, 06 Feb 2022 09:54:32 -0800) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<sr9qvg5gc3rues8uvihhuop496q51dt7hv@4ax.com>:
>On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje
><pNaonStpealmtje@yahoo.com> wrote:
>
>>On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin
>><jjlarkin@highlandtechnology.com> wrote in
>><l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>:
>>
>>>I might do the oscillator with an ECL comparator, which gets me the
>>>differential output. That could be RC, or LC.
>>
>>I have used the twisted wire oscillator, very stable too, tunable with a potmeter
>>causing Vce changes that result in Ccb Cce changes etc:
>> http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF
>> http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG
>>
>>For lower frequencies the twisted part is longer,
>>
>>Chip specs may change. add that ECL to make differential output.
>>There are probably a million types of oscillators, cavities come to mind too.
>
>We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
>diff outout pair was cross-connected to the input, and it oscillates
>at 1.5 GHz with a fairly square wave out the 2nd diff pair.
>
>Tempco is mediocre. An LC would probably help. Given that I currently
>need a 1.5 GHz clock, doing this might be risky.
>
>We'll try a comparator next.
>
>I could buy a commercial VCO, but they are expensive.
Yes
I have some Sirenza VCOs
vco190-1572t.pdf
https://www.ebay.com/itm/402975121352 about 17 canadian $
payed half that in 2013
There is a cheaper one at about 1.5 GHz on ebay, dont know how good it is:
https://www.ebay.com/itm/19141762235 about USD 8
And I have a 960 MHz vco190-964t.pdf
The twisted wire is cheaper :-)
Reply by whit3rd●February 6, 20222022-02-06
On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote:
> We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
> diff outout pair was cross-connected to the input, and it oscillates
> at 1.5 GHz with a fairly square wave out the 2nd diff pair.
>
> Tempco is mediocre. An LC would probably help. Given that I currently
> need a 1.5 GHz clock, doing this might be risky.
Huh? What is wrong with temperature coefficient in this application?
> We'll try a comparator next.
Logic isn't intended to oscillate without a network (because oscillation
forces the inputs into the logic margin, not a logically valid state).
The comparator DOES specify behavior at the threshold, so that's 'safe' in
a sense.
> I could buy a commercial VCO, but they are expensive.