Moin,
I need some formulas that relate EFC noise to the (added) phase noise of
an OCXO. It shouldn't be too difficult to come up with something. But
before I make some stupid mistakes, i wanted to ask whether someone
has already done this or has any references to papers? My google-foo
was not stro
In message <20160801154643.905ed816ac900a8d9a505...@kinali.ch>, Attila Kinali w
rites:
>I need some formulas that relate EFC noise to the (added) phase noise of
>an OCXO. It shouldn't be too difficult to come up with something. But
>before I make some stupid mistakes, i wanted to ask whet
Hi
It’s just very standard FM modulation math. The only gotcha is the
(often unknown) bandwidth of the EFC port. Even on a precision
OCXO, it might be <10 Hz, it might be over a KHz …. The trap many
fall into is the “small angle” restriction. You can get into modulation
indexes that will get th
On Mon, 01 Aug 2016 14:36:28 +
"Poul-Henning Kamp" wrote:
> >I need some formulas that relate EFC noise to the (added) phase noise of
> >an OCXO. It shouldn't be too difficult to come up with something. But
> >before I make some stupid mistakes, i wanted to ask whether someone
> >has already
A good filter in the cable is highly recommended, 5 KOhm & 1000 uF cleans
many things
In a message dated 8/1/2016 11:12:51 A.M. Eastern Daylight Time,
kb...@n1k.org writes:
Hi
It’s just very standard FM modulation math. The only gotcha is the
(often unknown) bandwidth of the EFC port.
Hi
….. until you discover that you picked the *wrong* capacitor manufacturer and
you have
more noise from leakage in the cap than you did to start out with :) In
general “big C and
small R” is the better solution than “big R and small C”.
The pesky part is that with electrolytic caps, the wh
On Mon, 1 Aug 2016 11:21:10 -0400
KA2WEU--- via time-nuts wrote:
> A good filter in the cable is highly recommended, 5 KOhm & 1000 uF cleans
> many things
Uhmm.. with 1mF in capacitors... don't you run into into microphonics problems?
Or all these capacitors supposed to be tantalum/aluminium
In message <20160801180601.3d27b82227616e847f340...@kinali.ch>, Attila Kinali w
rites:
>On Mon, 1 Aug 2016 11:21:10 -0400
>KA2WEU--- via time-nuts wrote:
>
>> A good filter in the cable is highly recommended, 5 KOhm & 1000 uF cleans
>> many things
>
>Uhmm.. with 1mF in capacitors... do
On 8/1/16 8:18 AM, Attila Kinali wrote:
On Mon, 01 Aug 2016 14:36:28 +
"Poul-Henning Kamp" wrote:
I need some formulas that relate EFC noise to the (added) phase noise of
an OCXO. It shouldn't be too difficult to come up with something. But
before I make some stupid mistakes, i wanted to a
I don't have the answer of the top of my head, but phase noise of VCOs and
PLLs is well documented. Perhaps "loop filter noise vco" or the like may
help.
On Mon, Aug 1, 2016 at 11:18 AM, Attila Kinali wrote:
> On Mon, 01 Aug 2016 14:36:28 +
> "Poul-Henning Kamp" wrote:
>
> > >I need some fo
This duplicates the problems encountered when trying to quantify low
frequency noise from a voltage reference; it is difficult to make an
low frequency high pass filter with lower noise than the lowest noise
references and the capacitor is the problem.
In Linear Technology Application Note 124, Ji
Hi
If you wire up all the possible circuits and check them all out … the
answer is that big C / small R wins. Big R gets you into resistor noise issues
and stray pickup.
Bob
> On Aug 1, 2016, at 4:16 PM, David wrote:
>
> This duplicates the problems encountered when trying to quantify low
>
Hi
If you are in the region that a low noise reference will apply to a low
deviation precision standard, you are
deep into “small angle” territory. The higher order stuff simply does not
apply. Rotate the spectrum by 1/f
(FM -> PM) and calculate the level at 1 Hz …..end of story. If when you a
The broadband thermal noise at a circuit point with a cap is always kT/c
On Monday, 1 August 2016, Bob Camp wrote:
> Hi
>
> If you wire up all the possible circuits and check them all out … the
> answer is that big C / small R wins. Big R gets you into resistor noise
> issues
> and stray pickup.
HI
Broadband is not where you run into the trouble on any of these circuits. It’s
always what happens within a decade or two past cutoff or inside the pass band.
Bob
> On Aug 1, 2016, at 4:50 PM, Scott Stobbe wrote:
>
> The broadband thermal noise at a circuit point with a cap is always kT/c
With my filter , I had good success and 5 K is not too high , Ulrich
Sent from my iPhone
> On Aug 1, 2016, at 11:46 AM, Bob Camp wrote:
>
> Hi
>
> ….. until you discover that you picked the *wrong* capacitor manufacturer and
> you have
> more noise from leakage in the cap than you did to sta
Yep, it supports the big C (padded out with increasingly smaller caps) in
general wins. For two low pass filters, one with say 100nF and one with
10nF, same fc, the 100nF filter will have 10 times less noise power, or
sqrt(10) less rms noise. Near DC is another story.
On Mon, Aug 1, 2016 at 5:10 P
Am 01.08.2016 um 22:16 schrieb David:
This duplicates the problems encountered when trying to quantify low
frequency noise from a voltage reference; it is difficult to make an
low frequency high pass filter with lower noise than the lowest noise
references and the capacitor is the problem.
I beg
Are the EFC inputs all directly DC coupled to the varactor diodes
making them high DC impedance?
I always thought they should bring the varactor or EFC ground out as a
separate pin but I assume that since they do not, ground noise at
least within the oscillator does not limit performance.
In the
Hi
Ultimately the EFC signal gets to one or more varicap diodes. It likely goes
through a bias or attenuator network to get there. Playing with the resistors
in the network allows the manufacturer to produce parts with consistent EFC
properties.
The pinout of your standard OCXO and it’s single g
davidwh...@gmail.com said:
> I always thought they should bring the varactor or EFC ground out as a
> separate pin but I assume that since they do not, ground noise at least
> within the oscillator does not limit performance.
I'm pretty sure I've seen comments, probably on this list, about troub
"I'm working on a new amplifier based on IF3602 or BF862 FETs that can
use 10u foil only."
Similar to that published by Groner in Linear Audio?
Bruce
On Tuesday, 2 August 2016 12:12 PM, Gerhard Hoffmann wrote:
Am 01.08.2016 um 22:16 schrieb David:
> This duplicates the problems encount
Am 02.08.2016 um 02:42 schrieb Bruce Griffiths:
/"I'm working on a new amplifier based on IF3602 or BF862 FETs that can
use 10u foil only."/
/
/
Similar to that published by Groner in Linear Audio?
/
/
I know that Groner exists from some web site, but had no personal contact.
Also I don't read L
Ja Gerhard, bitte schicke mir den LTSpice file,
Danke im Voraus und
73
KJ6UHN
Alex
On 8/1/2016 6:34 PM, Gerhard Hoffmann wrote:
Am 02.08.2016 um 02:42 schrieb Bruce Griffiths:
/"I'm working on a new amplifier based on IF3602 or BF862 FETs that can
use 10u foil only."/
/
/
Similar to that publi
Gerhard, please send me the LTspice files, so I can compare it with some of
my circuits.
The Groner preamp uses feedback to adjust the dc input at the input
(paralleled) FET gate(s) to adjust the dc output to zero. It uses a small
value input coupling capactor with a high value resistor to bi
Gerhard wrote:
The preamp will be classical. Some JFETs in parallel * * *
Cascode with a Zetex bipolar (or whatever they are called now).
* * *
Without the cascode, the 1 MHz is not possible. It does not help that
the feedback limits the voltage excursions on the drain.
As you recog
Am 02.08.2016 um 09:14 schrieb Bruce Griffiths:
... and a screen dump for the LTspice challenged
;-) Gerhard
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On Tuesday, August 02, 2016 01:03:58 PM Gerhard
Hoffmann wrote:
> Am 02.08.2016 um 09:14 schrieb Bruce Griffiths:
>
>
> ... and a screen dump for the LTspice challenged
>
> ;-) Gerhard
Uually a zero is needed in the bias stabilisation loop to
eliminate low frequency gain peaking.
Bruce
__
Am 02.08.2016 um 22:24 schrieb Bruce Griffiths:
Uually a zero is needed in the bias stabilisation loop to eliminate
low frequency gain peaking.
2 Meg across the 3.3uF remove the peaking. Nevertheless the circuit
still has
problems with its time constants. Weird things happen if you let the
Gerhard wrote:
... and a screen dump for the LTspice challenged
BTW, it can be a lot easier to create multiple, parallel devices in
LTspice by using the "m" command. (Multiple series devices -- passives
and diodes -- can be created with the "n" command.) The schematics look
cleaner, too.
Around 35 years ago, I worked with the guys
who designed and manufactured the 10811. There
are a couple of things here that don't add up,
subject to remembering stuff from a LONG time
ago:
1. Back in those days at least, there were
vendors who supposedly specialized in providing
low noise zener
One further point regarding noise from the EFC voltage: The varactor in
the oscillator will necessarily have a rather high resistance in series
with it, which adds a certain amount of unavoidable Johnson noise.
Also, the "other end" of the varactor is not generally grounded --
rather, it is con
Hi Rick:
My first engineering job was working on Tunnel Diode amplifiers at microwave frequencies (when transistors only worked
at audio frequencies). The bias circuit was a 5.1 Volt Zener and a series diode just as your describe for temperature
stability. There was also a BALCO (+ temp coeff
Am 03.08.2016 um 18:30 schrieb Richard (Rick) Karlquist:
1. Back in those days at least, there were
vendors who supposedly specialized in providing
low noise zener diodes. The particular breakdown
voltage of zener diodes was important. IIRC,
at low voltages, it is a true "zener" diode and
at
Rick wrote:
There are a couple of things here that don't add up,
subject to remembering stuff from a LONG time ago
One source of noise I didn't mention is leakage current in the varactor
itself. They are actually pretty noisy devices because of this. It's
entirely possible that the varacto
On Wed, 3 Aug 2016 14:01:30 -0400, you wrote:
>Rick wrote:
>
>...
>
>> Anyway, what I was led to believe is that
>> certain JEDEC 1N___ part numbers, with suffixes
>> indicating noise properties, from particular
>> vendors had much lower than average noise. Thus
>> if a run of the mill zener diod
Hi
Picking some random 10811-ish numbers:
10 MHz output
5V EFC range
1.6 ppm total EFC range
10 Hz offset from carrier
If you put in 300 nv of noise, in a 1Hz bandwidth, you get around -146 dbc of
phase noise. Your
OCXO would be doing very well at 10 MHz to run -135 dbc phase noise at 10 Hz.
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