Re: [Discuss-gnuradio] Troubled by the pfb channelizer center frequency location

[Tom Rondeau]

On Thu, May 16, 2013 at 12:26 AM, LD Zhang <address@hidden> wrote:
> I guess I got it! The default channel map is such that the first channel is
> the UN-fftshifted frequency location which is at 10 Hz (the 5th one on the
> list)! Whoo! It would be nice to tell a newcomer about this.
>
> LD
>

Glad you got it working.

You could have read the documentation on the block, though:
http://gnuradio.org/doc/doxygen/classgr_1_1filter_1_1pfb__channelizer__ccf.html

Look at the 'set_channel_map' function. It explains the channel
mapping; and how to change it.

Tom


>
> From: LD Zhang [mailto:address@hidden
> Sent: Wednesday, May 15, 2013 4:16 PM
> To: discuss-gnuradio Discussion Group
> Subject: Troubled by the pfb channelizer center frequency location
>
>
>
> Dear Group,
>
> I am learning to do the pfb channelizer using the now famous example on the
> documentation page at:
>
> http://gnuradio.org/doc/doxygen/page_pfb.html
>
> The example is at the end of the page, where a 9-subchannels are pulled out
> of the original 9 kHz bandwidth signal. The original signals' tones are at
>
> [freqs = [-4070, -3050, -2030, -1010, 10, 1020, 2040, 3060, 4080]
>
> The original signal bandwidth should be from -4500 to 4500 Hz.
>
>
>
> According to my understanding the first channel signal should be centered at
> -70 Hz, since the 9 channels' centers should be at [-4000, -3000, ..., 3000,
> 4000].
>
> But the output plot from the example shows that the first tone is at
> slightly greater than 0 Hz frequency.
>
> I don't know what is going on here?
>
> LD
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>