Re: [Discuss-gnuradio] operation order in freq_xlating_fir

[Tom Rondeau]

On Thu, Feb 24, 2011 at 12:18 PM, Alberto Trentadue
<address@hidden> wrote:
> Hello
>
> Just to make sure, may anybody please confirm the sequence of operations 
> within the freq_xlating_fir_filter?
>
> Is it:
> in --->XLATE--->FILTER--->DECIM---> out
>
> When defining the FIR taps with firdes, shall I consider the input sampling 
> freq or the output sampling freq (= input
> sampling freq / decim) ?
>
> Thanks in advance
>
> Alberto

Alberto,
Not having looked at the guts of this block for a while, I would hope that it's:

> in--->FILTER--->DECIM --->XLATE---> out

Since we would want to perform the frequency shift at the lower
sampling rate (it's easy enough to translate an LPF to a BPF). But the
implementation doesn't really matter for you main question. Either way
will work and will work the same. You'll want to specify the taps
based on the input sampling rate.

Tom