[time-nuts] low noise multiplication to 100 MHz
Bill
bill at hsmicrowave.com
Mon Jan 25 17:05:39 EST 2016
Aaah - but then you need a microprocessor (and its noise if you're not
careful) to control it. IMHO - too complicated an approach. Hard to beat
a "careful" straight multiplier approach for simple or a phased locked
100 MHz VCXO for the best phase noise.
Bill - N6GHz
On 1/25/2016 9:20 AM, Graham / KE9H wrote:
> There are clock distribution parts designed to do this low noise frequency
> conversion and distribution.
>
> Consider TI LMK04100
>
> Ignore PLL1
> Put your 10 MHz as the reference input to PLL2.
> Set Internal VCO to ~1200 MHz
> Set the internal dividers to get 100 MHz out, and 10 MHz back to the PLL2
> phase detector.
>
> Get reasonable noise and 100 MHz output with your choice of 2VPECL, LVDS,
> LVCMOS output levels.
>
> If you have a dirty input clock/reference, or multiple sources, you can use
> PLL1 and an external crystal in a VCO to clean it up before you multiply it
> to 1200 MHz.
>
> And you can get up to four other frequencies out of the part at the same
> time.
>
> 150 fs class jitter.
>
> $13 cost, quantity one.
>
> --- Graham
>
> ==
>
>
>
>
>
> On Mon, Jan 25, 2016 at 9:22 AM, Bert Kehren via time-nuts <
> time-nuts at febo.com> wrote:
>
>> If not good enough an XOR with filter and one of the Crystek VCXO's
>> previously mentioned may do it.
>> Bert Kehren
>>
>>
>> In a message dated 1/25/2016 10:01:33 A.M. Eastern Standard Time,
>> magnus at rubidium.dyndns.org writes:
>>
>> Also, it will be systematic, with idle tones. Because of the delay
>> elements used, they will not be long-term static but move around.
>>
>> I agree, this is quite noisy. If the noise is tolerable, it is indeed a
>> small solution. 100 ps 1-sigma for 5 MHz in 100 MHz out isn't what I
>> would consider low.
>>
>> https://www.idt.com/document/dst/570-datasheet
>>
>> Cheers,
>> Magnus
>>
>> On 01/24/2016 11:12 PM, Bruce Griffiths wrote:
>>> Unfortunately the ICS570 (like all zero delay buffers) has an output
>> jitter approaching about 1000 times the likely RF ADC internal sampling
>> jitter. The resultant SNR degradation may be a little excessive for this
>> application..
>>> Bruce
>>>
>>>
>>> On Monday, 25 January 2016 11:00 AM, Bert Kehren via time-nuts
>> <time-nuts at febo.com> wrote:
>>>
>>> With all the discussions in a small 100 MHz source I asked my project
>>> partner Juerg in Switzerland to run some data on the ICS 570 that we use
>> on the
>>> majority of our projects with excellent results. Using the HP53132A we
>> see
>>
>>> + - 1 count at E10-11 ignore the large jumps those come from the Tbolt
>>> frequency change to correct the 1 pps. Depending on the application
>> this is an
>>> excellent device.
>>> Bert Kehren
>>>
>>>
>>> In a message dated 1/23/2016 6:02:23 P.M. Eastern Standard Time,
>>> dk4xp at arcor.de writes:
>>>
>>> Am 22.01.2016 um 22:40 schrieb jimlux:
>>>> the oscillator is a HCMOS output, so figure swinging about 3.5V
>>>> Output.. I'm feeding differential clock inputs on ADCs. I'll bet a
>>>> +/- 300mV swing would work.
>>>>
>>>>> 4)Title said "Low Noise" needs better definition as to what kind of
>>>>> noise and how far down. Are we to be concerned about harmonic and
>> spur
>>>>> content as compared to real random white noise?
>>>> This is time-nuts.. it has to be perfect..
>>>>
>>>> But realistically, my source is probably going to be about -90dBc/Hz
>>>> at 1 Hz, -125 at 10Hz, -145 at 100 Hz. I'm going up by a factor of
>>>> 10, so I'd expect 20 dB worse plus a little..(nothing is perfect,
>> eh?)
>>>> Call it maybe -100 to -95 at 10 Hz, -125 to -120 at 100 Hz and so
>> forth.
>>>> harmonics are interesting: it's the sample clock into an ADC. So
>>>> harmonics of the 100 aren't a big deal. harmonics of the 10 or 20
>>>> are. If you have significant 90 or 110 contaminating the 100, then
>>>> you get weird spurs.. (I had this problem on a software radio where
>>>> the 50 MHz sample clock was contaminated with some 66 MHz from the
>> CPU)
>>>> Spurs cause the same issues.
>>>>
>>>> ON the other hand... spurs that are pretty low don't make much
>>>> difference if you're digitizing a signal that is close to the noise
>>>> floor: the spur multiplied by the desired signal is usually lower and
>>>> down in the noise. Strong CW in band signals, though, are a real
>> pain.
>>>>
>>> <
>>>
>> https://picasaweb.google.com/103357048842463945642/Tronix#607927018804883377
>>> 8
>>> I think that top left board would not be far away:
>>>
>>> in : 10 MHz LVDS or CMOS
>>> in: 3V3
>>> out: 100 MHz CMOS 3V3
>>>
>>> just a few hours wall clock time from layout to working as a
>>> ham radio weekender, so please excuse my diy home board
>>> production process.
>>>
>>> Ok, the use of a 4046 descendant may not be the last word
>>> from a timenut perspective, but I'll redo it with an osc of
>>> my own anyway. Divider 100/10 is a LVC163 (161?) + lvc04.
>>>
>>>
>>> < http://www.crystek.com/crystal/spec-sheets/vcxo/CVHD-950.pdf >
>>>
>>> Digi-Key has 153 of them on a tape and 441 of a similar one , even
>>> cheaper that seems to point to the same data sheet.
>>>
>>> <
>>>
>> http://www.digikey.de/product-detail/de/CVHD-950-100.000/744-1213-ND/1644128
>>> You can get the few dB missing close-in by transfer from your
>> reference.
>>> In the picture:
>>> The bottom row of boards is a doubler 100->200 MHz using 2*BF862,
>> slight
>>> gain,
>>> and diode doubler 200 -> 400 MHz, SAW filter to get rid of
>>> 100/200/300/500/600 +/-10 etc,
>>> post amp to get a usable level again.
>>>
>>> Still missing 400-> 800, 800->1600 to feed _my_ ADC clock input..
>>>
>>> regards, Gerhard
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the time-nuts
mailing list