Reference documents for the interpolation filter in the digital clock recovery block

Hi all,

I am a new one to GnuRadio. Now I am studying some implemented
techniques
in GnuRadio, one of them is the digital clock recovery. I would like to
ask
you a question that what are the reference documents or papers you used
for
the interpolation filter in that task (digital clock recovery). When I
traced back the source files - digital_clock_recovery_mm_ff and
then gri_mmse_fir_interpolator, I found only a little information:

  • This implements a Mininum Mean Squared Error interpolator with 8
    taps.
  • It is suitable for signals where the bandwidth of interest B =
    1/(4*Ts)
  • Where Ts is the time between samples.

I find it tough to understand the algorithm you selected, so could you
please help me on this problem. I make a guess with the key words "
Mininum
Mean Squared Error", the implementation may have some link to those
below
papers:
[1]. G. Watkins, Optimal Farrow coefficients for symbol timing
recovery, IEEE
Communications Letters
, vol. 5, no. 9, pp. 381383, Sep. 2001.
[2] Daeyoung Kim, M. J. Narasimba, and D. C. Coc, Design of optimal
interpolation filter for symbol timing recovery, IEEE Transactions on
Communications, vol. 45, no. 7, pp. 877884, Jul. 1997.

I would like to thank you very much in advance,

With best regards,

Nguyen Anh Duc

On Wed, Mar 14, 2012 at 10:42 PM, Anh Duc N. [email protected]
wrote:

  • It is suitable for signals where the bandwidth of interest B = 1/(4*Ts)
    interpolation filter for symbol timing recovery, IEEE Transactions on
    Communications, vol. 45, no. 7, pp. 877884, Jul. 1997.

I would like to thank you very much in advance,

With best regards,

Nguyen Anh Duc

I’m afraid that’s before my time. I’m not sure we have the corporate
knowledge on that anymore.

If you find a good paper to describe it, let me know and I’ll put it
into
the documentation like we’ve done elsewhere.

Thanks,
Tom

On Fri, Mar 16, 2012 at 05:36, Tom R. [email protected] wrote:

I’m afraid that’s before my time. I’m not sure we have the corporate
knowledge on that anymore.

If you find a good paper to describe it, let me know and I’ll put it into
the documentation like we’ve done elsewhere.

A wee bit of archaelogical digging recovers these two ancient
documents from the lowermost layer of strata in the code (from back in
2002):

http://gnuradio.org/cgit/gnuradio.git/tree/gnuradio-core/src/gen_interpolator_taps/README
http://gnuradio.org/cgit/gnuradio.git/tree/gnuradio-core/src/gen_interpolator_taps/praxis.txt

Johnathan

Dear all,

I am sorry for my late appreciation. Thank you very much for your prompt
and valuable information, I believe your kind support will help us, the
new
beginners, much to get used to gnuradio much faster.

With best regards,

On Fri, Mar 16, 2012 at 11:20 PM, Johnathan C. <

On Fri, Mar 16, 2012 at 12:20 PM, Johnathan C. <
[email protected]> wrote:

2002):

http://gnuradio.org/cgit/gnuradio.git/tree/gnuradio-core/src/gen_interpolator_taps/README

http://gnuradio.org/cgit/gnuradio.git/tree/gnuradio-core/src/gen_interpolator_taps/praxis.txt

Johnathan

Good catch. I’m just going to put a pointer into the documentation of
the
gri_mmse_fir_interpolator to those files.

Tom