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Re: LF: T/A ... and uHz grabber

To: [email protected]
Subject: Re: LF: T/A ... and uHz grabber
From: Scott Tilley <[email protected]>
Date: Sun, 18 Sep 2011 02:51:35 -0700
In-reply-to: <87921B1A33264C65B0A8BBEBBCBD1A04@White>
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On 9/17/2011 1:54 PM, Markus Vester wrote:
Scott, the slow SpecLab settings are fairly straightforward - I use 11025 Hz samplerate, complex decimation by 768, FFT size 32768, and 600 seconds per FFT.
Gotcha...  What I needed to reduce implementation time...  Mind you, I'll need to run at a higher sample rate, see below...

 The center frequency and display offset will depend on your receiver's precise LO frequency (watch out for DDS rounding errors).

132.000KHz. Will look at the actual 'delta phase word' and calculate true LO QRG for use as the new offset.
Finally you will want to inject a known audio tone for samplerate tracking (eg. GPS-derived 5 kHz), or alternatively 1-pps pulses plus NMEA (which I haven't tried yet).
 

A GPS derived 10KHz signal is already injected into the audio stream and used for sample rate tracking on all grabber plots...  So good to go here...

I should have time to setup in a couple of days.

Scott

PS - YO 153KHz broadcaster noted for the first time this season.



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