Hello Joe (and the whole bunch),
We can go for 2 out of 3, with possebly buffering or so, as there are little
SMD blocks containing Xtal and oscillator chip, virtually a one component Xtal
oscillator that can be useful for osc nr 2. Conrad.com sels them for 1 to 3
Euro, single item price. They only do not have the exact frequencies of 55 or
35 MHz, but I hope there are outlets that are better sorted.
But whatever we do here, it will not interfere with the construction and layout
of the motherboard , so that can go on. As long as we agree on the interface
with the motherboard, and stick to that.
I see this oscillator sub-board as a rectangular board, standing on one of the
long sides, not higher than 2 or 3 cm so it fits inside a shielding box, with
some pins in the motherboard, 3 pins for signal and close by 3 ground pins,
then somewhere on one end of the board power supply pins. The clock and data
lines comes directly from the digital board, mounted on the front panel and
housing the processor and LCD. And should be shielded from the analog part of
the set as this whole digital circuit radiates the 16 MHz clock frequency.
That is the reason I like to split the whole set in an analog and digital part.
(With a solid shield inbetween)
Somebody might contact the si manufacturer and ask if they have an application
note for this chip, explaning how to prevent or get around this crosstalk.
I am interested to hear what Ashhar will think of our idear to use the si5351,
as I remember well, he rejected this chip some year ago because of the
crosstalk.
Regards Ben PA9B (in Turkije)
-------- Origineel bericht --------
Van:Joe Rocci <joe@xxxxxxxxxx>
Verzonden:Thu, 02 Jun 2016 03:18:46 +0300
Aan:minima@xxxxxxxxxxxxx
Onderwerp:[minima] Re: looking for HF1
Ben
I don't have a dog in the fight, so I'll defer the modularity and
component-type selection to you. Sounds like an interesting version though. I
did want to point out my personal experience with the Si5351. It's usable, but
not spectacular. Having said that, I have a phasing-method rig on the bench
that uses it and I'm happy with the performance so far. Numbers to follow some
day.
Joe
Sent from my Verizon Wireless 4G LTE Tablet
-------- Original message --------
From: Ben Aupperlee <beninturkye@xxxxxxxxx>
Date: 06/01/2016 7:23 PM (GMT-05:00)
To: minima@xxxxxxxxxxxxx
Subject: [minima] Re: looking for HF1
Hi Joe,
Yes, but we came from a situation where we had an X-Tal oscillator for nr2,
and the idea was: replace it with a chip and save a lot of board space an
discreet components. On the other hand this might solve the crosstalk problem.
Are we going to place a lot discrete components on that small SMD board, or
will we put them on the motherboard and only use the smd board for osc 1 and 3.
Groetjes Ben (in Turkije)
-------- Origineel bericht --------
Van:Joe Rocci
Verzonden:Thu, 02 Jun 2016 02:03:59 +0300
Aan:minima@xxxxxxxxxxxxx
Onderwerp:[minima] Re: looking for HF1
Ben
Oscillator #2 doesn't have to be variable, or even very accurate. A simple
crystal oscillator will do and you can still do passband tuning. I suggest
this because the Si5351 will probably have horrible crosstalk spurious if all
3 oscillators are running. It's much better if you just run #0 and #2 and keep
the output traces well isolated from each other. In the. Si570 approach, this
eliminates an expensive 3rd part.
Joe
Sent from my Verizon Wireless 4G LTE Tablet
-------- Original message --------
From: Ben Aupperlee <beninturkye@xxxxxxxxx>
Date: 06/01/2016 6:45 PM (GMT-05:00)
To: minima@xxxxxxxxxxxxx
Subject: [minima] Re: looking for HF1
Hello Ashhar,
I had some exchange of idears about SMD and modules, so here a new version
with a new drawing, the old .gif is also used in this temp.htm text.
Regards Ben PA9B (in Turkije)
