[time-nuts] Down-conversion to IF and sampling

Stephan Sandenbergh ssandenbergh at gmail.com
Sat Dec 23 10:46:15 EST 2017


Oops, I noted a sign error in the previous diagram. The attached seems
better...

On Sat, Dec 23, 2017 at 4:46 PM Stephan Sandenbergh <ssandenbergh at gmail.com>
wrote:

> Hi All,
>
> Consider the following very common scenario: A perfect RF signal is
> heterodyne down-converted to baseband using an offset oscillator. Let's
> assume this oscillator has x(t) = xo + yot. This produces a time and
> frequency offset baseband signal. Then, this baseband signal is coherently
> ADC sampled using that same offset oscillator.
>
> What would the effect of this coherent ADC sampling be?
>
> See attached diagram. Here I assumed the ADC timebase is a time-dependent
> function of the oscillator offset. However, it feels like I'm making a
> logic error? I can't remember ever seeing anyone accounting for the ADC
> time-base errors in coherent heterodyne down-converter stages. I have
> limited experience though.
>
> Regards,
>
> Stephan.
>
>
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: img1.png
Type: image/png
Size: 21091 bytes
Desc: not available
URL: <http://www.febo.com/pipermail/time-nuts/attachments/20171223/88d9a784/attachment.png>


More information about the time-nuts mailing list