Default value of fft_length

GNU Radio
1

Hi,

I want to double check that if the default value of fft_length for the
ofdm is 512 ?

Thanks

Chin-Ya

2

On Sat, May 17, 2008 at 01:07:29AM +0800, Chin-Ya Huang wrote:

Hi,

I want to double check that if the default value of fft_length for the ofdm is 512 ?

Thanks
Chin-Ya

If you care, you should specify it. Don’t count on the default never
changing.

Investing two minutes looking at code reveals that ofdm.py defaults it
to 512.

def add_options(normal, expert):
    """
    Adds OFDM-specific options to the Options Parser
    """
    normal.add_option("-m", "--modulation", type="string",

default=“bpsk”,
help=“set modulation type (bpsk or qpsk)
[default=%default]”)
expert.add_option("", “–fft-length”, type=“intx”, default=512,
help=“set the number of FFT bins
[default=%default]”)
expert.add_option("", “–occupied-tones”, type=“intx”,
default=200,
help=“set the number of occupied FFT bins
[default=%default]”)
expert.add_option("", “–cp-length”, type=“intx”, default=128,
help=“set the number of bits in the cyclic
prefix [default=%default]”)

I used a very special tool to figure this out: grep
It’s probably installed on your system too…

Eric

3

On Sun, May 18, 2008 at 12:38:46AM -0700, Eric B. wrote:

It’s probably installed on your system too…

Apologies to Chin-Ya and everybody else for the tone of my reply.

Eric