Hi
I seem to recall TI having similar parts.
The big gotcha is tossing large chunks of C onto the ground to rail
connections. A typical op amp is not at all happy with this.
Bob
> On Jul 10, 2022, at 5:48 PM, Richard (Rick) Karlquist via time-nuts
> wrote:
>
>
>
> On 7/10/2022 10:14 AM,
On 7/10/2022 10:14 AM, Lux, Jim via time-nuts wrote:
Yeah, but that virtual ground brings with it it's own set of problems.
For instance, it has to both sink and source current, so you can't just
use a 3 terminal regulator to create the midpoint, although I've seen
schemes with a resistor
Hi Ed,
On 7/10/22 20:26, ed breya via time-nuts wrote:
Hi Magnus,
I know what you mean about not needing a quadrature splitter - if you
have a very wide phase or delay tuning range - but I'm picturing
getting most of the way to quadrature with a fixed structure for a
given frequency, and
Hi
If you dig into the various books on phase noise, they do go into other
ways to measure it. The bottom line is that things like frequency discriminators
are quite noisy (floor wise) compared to a single mixer.
Bob
> On Jul 10, 2022, at 10:26 AM, ed breya via time-nuts
> wrote:
>
> Hi
I've ALWAYS used an op-amp to nail down the half rail supply, I never
use the two resistors and cap idea directly unless the whole thing is
quite basic
Just don't put bulk capacitance on the output !
like I have seen in some bad designs. ROFL.
Some op-amps are better at this than
Hi Erik,
On 7/10/22 17:52, Erik Kaashoek via time-nuts wrote:
I've updated the schematic to include the latest additions and added
some new measurements
Schematic: http://athome.kaashoek.com/time-nuts/PNA/Simple_PNA.pdf
The resistor values (many 18k) are a bit weird but I happen to have a
Hi Magnus,
I know what you mean about not needing a quadrature splitter - if you
have a very wide phase or delay tuning range - but I'm picturing getting
most of the way to quadrature with a fixed structure for a given
frequency, and only fine-tuning the phase over a narrow range, in order
Hi
There’s really no need to use the Vref out of the OCXO at all.
Since many devices don’t have one, you will need a “replacement”
at some point. Simply pulling the “set reference” off of a cleaned
up output of your main supply(s) is typically how it is done.
The most basic reason to not hard
On 7/10/22 9:07 AM, Bob kb8tq via time-nuts wrote:
Hi
Yes it is a pain to implement dual supplies. I ponder that issue every time
I build one of these setups. I’ve built a lot of them …. If you are going to
do a single supply, setting up a “virtual ground” is probably the best way
to go. Do it
Hi
Pretty much the best mixer to use for this in a basement / DIY basis
is a Mini Circuits RPD-1 or one of it’s siblings. It has a 500 ohm
output on the mix port instead of 50 ohms. Yes, you open circuit
terminate it ( so 5K ) but as noted, it’s the Zout of the mixer that likely
sets what the op
Hi
Yes it is a pain to implement dual supplies. I ponder that issue every time
I build one of these setups. I’ve built a lot of them …. If you are going to
do a single supply, setting up a “virtual ground” is probably the best way
to go. Do it with a drive circuit to provide very clean 15V off
I've updated the schematic to include the latest additions and added
some new measurements
Schematic: http://athome.kaashoek.com/time-nuts/PNA/Simple_PNA.pdf
The resistor values (many 18k) are a bit weird but I happen to have a
big box of 18k resistors.
The value of the low pas filter after
Am 2022-07-10 9:11, schrieb Erik Kaashoek via time-nuts:
@Bob,
You mentioned "dual supplies with high voltage" for the first gain
opamp. How much impact would dual voltage bring as its a pain to
implement.
I think is was Rubiola who wrote that he exploded a costly microwave
mixer
with a
How can you measure something, any type of measure, not only PN,
without a reference? Voltmeters need voltage references, "timemeters"
(and frequency meters) need time references.
On Sun, Jul 10, 2022 at 1:47 AM ed breya via time-nuts
wrote:
>
> I've been following the thread about Erik's DIY PN
Dear Time-Nuts,
many thanks for the amazing amount of interest!
My son will draw lots today and I´ll notify the "winners".
Have a nice Sunday,
Matthias
Am 09.07.2022 um 14:59 schrieb Matthias Jelen via time-nuts:
Dear Time-Nuts,
I need to generate some space in my basement...
I have
Hi Magnus,
Yes, and it works very well, locking is easier as once locked it nicely
stay's in lock, , even with a slow drift of either the DUT or the
reference. As I could not find a bipolar capacitor the tuning potmeter
has to be kept at the low side to avoid blowing the integration
Ed,
On 7/9/22 22:26, ed breya via time-nuts wrote:
I've been following the thread about Erik's DIY PN analyzer, and
wondering if it might be easy enough to use a frequency discrimination
method. I'm opening this in a different thread to avoid muddying the
water on the original (and long) one.
Erik,
On 7/9/22 22:06, Erik Kaashoek via time-nuts wrote:
Getting the simple PNA to lock was a bit difficult due to the overly
simplistic translation of the mixer output to the Vtune of the OCXO
To get some more flexibility I added a summing opamp that summed the mixer
output with the output of
On Sonntag, 10. Juli 2022 01:24:49 CEST djl via time-nuts wrote:
> I checked the Hittite/AD part at Mouser, $21 and change. Problem is,
> they have a few, but it is marked obsolete/discontinued. Also, a
> devilish package to work with. . .
For a one-off project, lifetime doesn't really matter,
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