[hpsdr] Software Radio, Mixers and oscillators

[KA2WEU at aol.com]

_http://www.rsd.de/www/dev_center.nsf/frameset?OpenAgent&website=com&navig=/ww
w/dev_center.nsf/html/nav,10,11,113&content=/www/dev_center.nsf/html/xk2100l_ 
(http://www.rsd.de/www/dev_center.nsf/frameset?OpenAgent&website=com&navig=/ww
w/dev_center.nsf/html/nav,10,11,113&content=/www/dev_center.nsf/html/xk2100l) 
 
 
 
 
This is my software radio  on which  I worked with the  R&S team for the last 
10 years with updates. The RF speech processor   gives it the same "punch"  
as a 1 KW  output ham radio  like ICOM  with processor ON. The most difficult 
thing was the AGC behavior, no overshoots  and the time constants. The filter 
with 6/60dB shape factors  of 1:1.2 with  flat group delay were tricky. Give ma 
a telephone  number and we can talk  ...
 
I will reply in the next week with more  details to your request.  Thanks for 
sharing this with me.
 
73 de N1UL
 
 
 



Hi Ulrich,
 
Please let me add my warm welcome to the group as well.  Your work has  been 
an inspiration to me for many years. As I young ham I built the synthesised  
transceiver that you published in Ham Radio in the 70's. I used it as my main  
radio for many years and it was my pride an joy. 
 
The are a couple of areas where I would appreciate your comments.   Firstly 
is the local oscillator for  HF use. This is intended to divide  down a GHz 
VCO. A discussion paper is at 
 
< _http://www.hamsdr.com/dnld.aspx?id=356_ 
(http://www.hamsdr.com/dnld.aspx?id=356)   >
 
 
One problem already pointed out is that we can't divide the 10MHz GPS  locked 
reference within the LMX25** to give us an 800kHz reference. We could  either 
use 400kHz steps and re do the math or double to 20MHz ( or phase lock a  
20MHz VCXO to the 10MHz reference)  and stay with 800kHz steps.
 
The second is the design of the preamp for the high speed ADC front end.  
Here we are using an LT2208 135MSPS 16 bit A/D converter. My initial tests  
indicate a 100dB dynamic range with an overload point of 0dBm. Please see the  
discussion on the Wiki at 
 
< _http://hpsdr.org/wiki/index.php?title=HpsdrWiki:Community_Portal_ 
(http://hpsdr.org/wiki/index.php?title=HpsdrWiki:Community_Portal)  >
 
under Mercury.
 
Your comments on the gain/attenuation prior to the ADC would be  appreciated. 
 
73's Phil...VK6APH 
 
 
 
 

----- Original Message ----- 
From:  _KA2WEU at aol.com_ (mailto:KA2WEU at aol.com)   
To: _hpsdr at hpsdr.org_ (mailto:hpsdr at hpsdr.org)  
Sent: Saturday, July 08, 2006 10:25  PM
Subject: [hpsdr] Software Radio, Mixers  and oscillators


***** High Performance Software Defined Radio Discussion List  *****

 
____________________________________

Hi guys
 
let me know if I can help with mixers or oscillators 
 
 
_http://synergymwave.com/default.asp_ (http://synergymwave.com/default.asp) 
 
Ulrich L. Rohde, N1UL


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