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Re: [Discuss-gnuradio] Transmit filtering
From: |
John Ackermann N8UR |
Subject: |
Re: [Discuss-gnuradio] Transmit filtering |
Date: |
Mon, 5 Sep 2011 12:55:00 -0400 |
Hi Marcus --
I am selecting complex taps from the drop down, but still get an error at
runtime if either cutoff frequency is 0 or smaller.
Thanks,
John
----
On Sep 5, 2011, at 11:46 AM, "Marcus D. Leech" <address@hidden> wrote:
> On 05/09/11 10:19 AM, John Ackermann N8UR wrote:
>> I'm generating two NBFM signals, offsetting them plus and minus 25 kHz
>> with FreqXlatingFilters, and combining the output in an adder which
>> then drives a USRP sink. It seems sensible to put a bandpass filter
>> on the result.
>>
>> I have a basic conceptual confusion. I would think that you'd specify
>> a bandpass filter around zero with a low cutoff of, say, -40e3 and a
>> high cutoff of +40e3. However, this doesn't work -- the bandpass
>> filter seems to require a number >0 for the lowpass frequency.
> Make sure that you specify complex-taps. I assume you're using GRC. By
> default, it uses the version of
> the bandpass filter with real taps. But if you specify complex taps,
> you can use negative frequencies.
>
>
> --
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org
>
>
>
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