[Discuss-gnuradio] DC-block block

[Marcus D. Leech]

I'm wanting to use the DC-block block, and I have questions about its use.

My scenario is to use it as a cheap high-pass, with a corner frequency 
of a few milli-hertz, with samples arriving at 50Hz.

It's not clear how the "length" parameter relates to the desired corner 
frequency and sample rate.

Another approach I was considering was to use a long-time-constant 
single-pole IIR, and subtract the output of that from the unmolested
  sample stream.

This is for a correlation interferometer, where we want to eliminate 
stability issues caused by low-level interference from satellite signals 
that basically show up as slowly-varying DC, at a frequency that's about 
1/10th the fringe frequency.