Hello Emil,
Forget the "VFO" field in your settings for the 8.27 kHz experiments
.. you don't need it (I guess) or do you really have an *external*
VFO ?
In the config posted on my website, the 8270 Hz center frequency is
achieved by the built-in NCO for the 'zoomed FFT'.
It multiplies the input with a complex NCO (8270 Hz), then decimates
down to a low sampling rate for the input to the FFT.
Just set the VFO frequency in the upper left corner to zero (which
is for an external frequency converter, SDR, USB receiver) to zero.
The summary of the FFT settings generates this output, copied from
the text panel on the "FFT" tab .. what is yours ?
FFT size = 16384 points
Center Frequeny = 8270 Hz
Input sampling rate = 48 kHz
Decimate input by 768
--->
Effect of FFT settings with fs= 62.5000 Hz:
Width of one FFT-bin: 3.81470 mHz
Equiv. noise bandwidth: 5.72205 mHz
Max freq range: 8.25437 kHz .. 8.28562 kHz
FFT window time (length): 4.369 min
73,
Wolf .
Am 22.01.2016 um 20:51 schrieb Emil
Focosi:
Hi Wolf,
I have set so SpecLab V278 to 8270 Hz Center frequency and bandwidth of 100 Hz:
vfo 5.523 Hz
fc
8.270 kHz
sp 100
Something wrong?
CU on 136 kHz
(Opera32) and 472 Khz (JT9-1 or CW)
73
Emil I5EFO
|
|
