[eagle] Re: The DS4000 Digital Controlled TCXO

Jim Sanford wb4gcs at amsat.org
Tue Jul 3 18:59:07 PDT 2007


Bill:
As usual, thanks for your cogent comments and suggestions.
73,
Jim


Bill Ress wrote:

>Hi Juan,
>
>The audio is a fantastic addition to your super analysis regime. Just 
>really fine work!!
>
>I've already addressed the issue of the two 10 MHz oscillators beating 
>as heard in clip #1.
>
>Now what you hear in the second audio clip doesn't surprise me. Just 
>another reason why I remain digitally challenged and analog biased.
>
>The DS4000 is a "digitally" corrected voltage controlled oscillator. I 
>believe what you are hearing is the frequency being corrected in finite 
>digital steps. An analog temperature corrected VCO will not do this. The 
>correction will be continuous and smooth. The key advantage of the 
>"digitally" corrected VCO is the ability to "remotely" correct the 
>frequency with a digital input. I would submit, that feature is not 
>needed for our application.
>
>The "analog" TCVCXO used in the S2 concept converter uses a low cost 
>device (available from several suppliers) and offers +/- 1 PPM stability 
>over temperature (-40 to 85 C).
>
>Regards...Bill - N6GHz
>
>Juan Rivera wrote:
>  
>
>>All,
>>
>>I should have gone to work today but I ended up working on the 70 cm 
>>Receiver all day instead. Today marks a milestone for me -- my first 
>>use of audio files. You'll find two in my write up if you click HERE 
>><http://www.juanr.com/pages/hobbies/ham_radio/Eagle/Stability.htm>. I 
>>think they work much better than descriptions and graphs. Now you can 
>>hear what I’m talking about...
>>
>>Have a great 4th! I plan to do a temperature run on the receiver 
>>tomorrow to celebrate! Let’s see what that internal oscillator does 
>>when it’s not at room temperature!
>>
>>P.S. to OSCAR guys... If you have time come on over and help me run 
>>this test. I’ll probably start early to beat the heat. If you’ve never 
>>been gassed by CO2 before, now is your chance!
>>
>>73,
>>
>>Juan – WA6HTP
>>
>>    
>>
>
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>
>  
>
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