Hi Graham,
Thanks for the advice. I've found a 74H00 in the junk heap and
will give the resonant ckt a try soon. It would be nice to use the DDS
for LO injection so that's why a higher clock freq is desirable. Does
anyone know if the 74HC00 chip is good to 30 MHz?
Are you are still looking for DDS via serial port control? You're
welcomed to my very inelegant basic program though Markus' version is
much nicer.
And the holy grail, which never gives sarcastic windoze backtalk nor
wastes your time booting on powerup, is an ardino board. It is small,
easy to program and you can do all sorts of wonderful things with a DDS.
73
Joe VO1NA
On Tue, 22 Jan 2013, Graham wrote:
Joe,
Looking at the app-sheet , there is a clock X 6 function , that would
put the 10 MHz up to 60 MHz , giving 100 :1 clock / out put ratio ?
this may be a PPL ?
Racal tended to use xtals , in there 'harmonic' generators ,
feeding a low freq sq wave , to a 2 stage xtal filter , xtals ring
in sync with the sq excitation , so phase locked as well .... 10 MHz
square wave to ... what .. say couple of high freq [cheap] xtals =
stable / clean HF clock ?
The holy grail would be some sort of 'pic' device that loaded the DDS
on power on , with a pre-set frequency , then you have a real xtal
replacement .. just needs to be fed its command word by something ?
73 -G..
http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds/ad9851/products/product.html
--------------------------------------------------
From: <[email protected]>
Sent: Tuesday, January 22, 2013 1:35 AM
To: <[email protected]>
Subject: Re: xxSPAMxx Re: LF: AD9850 controlled by RS-232
On Mon, 21 Jan 2013, [email protected] wrote:
Hi Markus,
but was toying with the idea of doing WSPR via the RS232 and AD09850...
an excellent idea!
On the other hand, having just looked at the DF6NM code for the dds and
WSPR and being most impressed by same, perhaps I should focus instead on
seeking stability and coherence.
The plan is to multiply a 10 MHz OXCO by three and feed it to an AD9851.
Could this be done with the gates of a TTL 7400 to take the sine to
a nice rich square then to a 30 MHz tuned circuit to an output gate to the
dds? Perhaps this is a silly idea. Either way, comments both
negative and favourable will be appreciated.
VX9MRC is still doing CW on 504.1 kHz. The carrier was generated by a home
brewed ad9850 with tiny connecting wires painstakingly soldered
to the pins. The boards Markus mentioned and Graham recommended a
while back are well worth their cost!
73
Joe VO1NA
This electronic communication is governed by the terms and conditions at
http://www.mun.ca/cc/policies/electronic_communications_disclaimer_2012.php
This electronic communication is governed by the terms and conditions at
http://www.mun.ca/cc/policies/electronic_communications_disclaimer_2012.php
|
