I would like to use gr_fractional_interpolator

But I get:

self.interp=gr.fractional_interpolator(

options.phase_shift,interp_ratio)

AttributeError: ‘module’ object has no attribute

‘fractional_interpolator’

Apparantly the module doesn’t exist anymore, although

gr_fractional_interpolator.h and gr_fractional_interpolator.cc exist.

I suspect there should also be a:

gr_fractional_interpolator.i

But I couldn’t find it in my source or any of the older gnuradio

releases I have laying around.

I know there is a rational_resampler in gnuradio now, but there you have

to give your interpolator taps.

The good thing of gr_fractional_interpolator is that it uses

mmse_fir_interpolator which has optimized performance for

low-tap-numbers.

Could anybody tell me how to get gr_fractional_interpolator to work or

where gr_fractional_interpolator.i is.

Greetings,

Martin

Martin D. wrote:

Apparantly the module doesn’t exist anymore, although

gr_fractional_interpolator.h and gr_fractional_interpolator.cc exist.

I suspect there should also be a: gr_fractional_interpolator.i

But I couldn’t find it in my source or any of the older gnuradio

releases I have laying around.

It doesn’t appear to have ever existed, as far as I can tell.

Everywhere fractional interpolation is used in the tree, the low-level

gri_mmse_fir_interpolator implementation is used.

The gr_ wrapper does look functional, but I just spotted a bug in its

constructor, so it looks like a work-in-progress that never got

finished.

Could anybody tell me how to get gr_fractional_interpolator to work

or where gr_fractional_interpolator.i is.

I’ll add getting this to work to my queue

–

Johnathan C.

Corgan Enterprises LLC

http://corganenterprises.com

Johnathan C. wrote:

It doesn’t appear to have ever existed, as far as I can tell.

Everywhere fractional interpolation is used in the tree, the low-level

gri_mmse_fir_interpolator implementation is used.

The gr_ wrapper does look functional, but I just spotted a bug in its

constructor, so it looks like a work-in-progress that never got finished.

Yes, I spotted it too now:

d_mu (phase_shift), d_mu_inc (interp_ratio), d_interp()

should be

d_mu (phase_shift), d_mu_inc (interp_ratio), d_interp(new

gri_mmse_fir_interpolator())

Could anybody tell me how to get gr_fractional_interpolator to work

or where gr_fractional_interpolator.i is.

I’ll add getting this to work to my queue

I don’t mind getting it to work myself.

I just don’t like inventing the wheel twice.

I will try to get it to work in my tree

branches/developers/nldudok1/general-wip

and let you know when its done.

Greetings,

Martin

On Fri, Mar 09, 2007 at 07:04:06PM +0100, Martin D. wrote:

I would like to use gr_fractional_interpolator

But I get:

self.interp=gr.fractional_interpolator( options.phase_shift,interp_ratio)

AttributeError: ‘module’ object has no attribute ‘fractional_interpolator’

Apparantly the module doesn’t exist anymore, although

gr_fractional_interpolator.h and gr_fractional_interpolator.cc

exist.

I suspect there should also be a:

gr_fractional_interpolator.i

This was apparently never finished or tested.

I understand that Johnathan has a patch that will fix this.

The underlying code is known to work.

But I couldn’t find it in my source or any of the older gnuradio

releases I have laying around.

I know there is a rational_resampler in gnuradio now, but there you

have to give your interpolator taps.

Actually, if you use blks.rational_resampler_fff it’ll design an

appropriate filter for you. See

gnuradio-examples/python/audio/test_resampler.py

The good thing of gr_fractional_interpolator is that it uses

mmse_fir_interpolator which has optimized performance for

low-tap-numbers.

Could anybody tell me how to get gr_fractional_interpolator to work

or where gr_fractional_interpolator.i is.

Greetings,

Martin

Eric

Martin D. wrote:

Yes, I spotted it too now:

d_mu (phase_shift), d_mu_inc (interp_ratio), d_interp()

should be

d_mu (phase_shift), d_mu_inc (interp_ratio), d_interp(new gri_mmse_fir_interpolator())

Yes.

I will try to get it to work in my tree

branches/developers/nldudok1/general-wip

My plan was to rename the existing one and create a second one, so we’d

have:

gr_fractional_interpolator_ff (the current one)

gr_fractional_interpolator_cc (the new one that does complex samples)

That will require some changes to the gri_mmse* code.

If you want to do this, have fun

–

Johnathan C.

Corgan Enterprises LLC

http://corganenterprises.com