[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Discuss-gnuradio] Re: ssb phasing demod revisited

From: Chuck Swiger
Subject: [Discuss-gnuradio] Re: ssb phasing demod revisited
Date: Sat, 26 Feb 2005 03:50:56 -0500

At 08:36 AM 2/26/2005 +0530, you wrote:
Will a seperate gr_delay.{cc,h,i| help? May be it is a much needed block, which
just takes the tap number.

You would have to ask Eric (I'm cc'ing the list) - From what I understand the issue isn't a seperate delay block, the one you have delays just fine - the issue is keeping it in lock-step phase sync with another seperate block, which is why Eric put Hilbert and
delay into one composite block. See this earlier discussion:

suppose I want to implement a simple
filter that performes a delay by 2 samples.

The correct coefficients are [0,0,1].
However, gnuradio will return
which is not what i want.

If I reverse the coefficients, I get [1,0,0]
which when used in gnuradio will return
which is not what we want either.

I think there's a bit of an impedance mismatch between how you are
thinking and how GNU Radio works.  GNU Radio is not an isochronous
data flow engine.  We've got lots of implicit buffering between
blocks.  You have virtually no control over the amount of buffering
that's taking place between blocks.  Thus, implementing a delay with the
filter block isn't going to get you what I think you want.  You're
probably noticed that there's no "delay" primitive.  If you've got
something with a feedback loop in it, it needs to be implemented in a
single block.  E.g., PLL's.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]