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Re: [Discuss-gnuradio] Xlate FIR filter broken in gr 3.7

From: Andrew Davis
Subject: Re: [Discuss-gnuradio] Xlate FIR filter broken in gr 3.7
Date: Thu, 8 Aug 2013 15:56:37 -0500

Center frequency of the received signal or center where I want to move it to? It's not intuitive ether way, the parameter name should be changed to what it actually is: 'frequency_shift' and it should behave exactly like multiplication does, you multiply a positive frequency you get a positive shift, negative frequency, down shift by that much, simple.


On Thu, Aug 8, 2013 at 3:45 PM, Tom Rondeau <address@hidden> wrote:
On Thu, Aug 8, 2013 at 4:37 PM, Stephen Harrison
<address@hidden> wrote:
> I agree.. the new way is more intuitive but then again it broke a bunch of
> my GRC patches.. :)
> On Thu, Aug 8, 2013 at 1:36 PM, Sylvain Munaut <address@hidden> wrote:
>> Hi,
>> > The "old style" version of the block in gnuradio-core in works
>> > correctly.  The "new style" version of the block in gr-filter in
>> > has the sign change.  When all the old-style blocks were removed for
>> > 3.7, this of course left only the changed one.
>> Personally I always thought that the previous block (in 3.6) was
>> "weird" because the parameter was named "Center freq" but you in fact
>> had to give it the frequency shift you wanted. The new one behaves
>> more like I expect.
>> Cheers,
>>     Sylvain

Yes, this change was made on purpose for exactly that reason. As
Johnathan noted, the new block after the 3.7 API change had this new
way of handling the parameter, but the old block didn't change (for
API compatibility reasons). I think the new way is more intuitive as
well since I, too, always messed it up myself. As Sylvain said, we
called it 'center frequency' but it was being treated as the value
used to actually shift the signal, not the center frequency of the

The real mistake here was not announcing this as a change in our 3.6 -
3.7 conversion document.

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